Redox-regulated Rotational Coupling of Receptor Protein-tyrosine Phosphatase α Dimers

Abstract

Receptor protein-tyrosine phosphatase α (RPTPα) constitutively forms dimers in the membrane, and activity studies with forced dimer mutants of RPTPα revealed that rotational coupling of the dimer defines its activity. The hemagglutinin (HA) tag of wild type RPTPα and of constitutively dimeric, active RPTPα-F135C with a disulfide bond in the extracellular domain was not accessible for antibody, whereas the HA tag of constitutively dimeric, inactive RPTPα-P137C was. All three proteins were expressed on the plasma membrane to a similar extent, and the accessibility of their extracellular domains did not differ as determined by biotinylation studies. Dimerization was required for masking the HA tag, and we identified a region in the N terminus of RPTPα that was essential for the effect. Oxidative stress has been shown to induce a conformational change of the membrane distal PTP domain (RPTPα-D2). Here we report that H2O2 treatment of cells induced a change in rotational coupling in RPTPα dimers as detected using accessibility of an HA tag in the extracellular domain as a read-out. The catalytic site Cys723 in RPTPα-D2, which was required for the conformational change of RPTPα-D2 upon H2O2 treatment, was essential for the H2O2-induced increase in accessibility. These results show for the first time that a conformational change in the intracellular domain of RPTPα led to a change in conformation of the extracellular domains, indicating that RPTPs have the capacity for inside-out signaling. Receptor protein-tyrosine phosphatase α (RPTPα) constitutively forms dimers in the membrane, and activity studies with forced dimer mutants of RPTPα revealed that rotational coupling of the dimer defines its activity. The hemagglutinin (HA) tag of wild type RPTPα and of constitutively dimeric, active RPTPα-F135C with a disulfide bond in the extracellular domain was not accessible for antibody, whereas the HA tag of constitutively dimeric, inactive RPTPα-P137C was. All three proteins were expressed on the plasma membrane to a similar extent, and the accessibility of their extracellular domains did not differ as determined by biotinylation studies. Dimerization was required for masking the HA tag, and we identified a region in the N terminus of RPTPα that was essential for the effect. Oxidative stress has been shown to induce a conformational change of the membrane distal PTP domain (RPTPα-D2). Here we report that H2O2 treatment of cells induced a change in rotational coupling in RPTPα dimers as detected using accessibility of an HA tag in the extracellular domain as a read-out. The catalytic site Cys723 in RPTPα-D2, which was required for the conformational change of RPTPα-D2 upon H2O2 treatment, was essential for the H2O2-induced increase in accessibility. These results show for the first time that a conformational change in the intracellular domain of RPTPα led to a change in conformation of the extracellular domains, indicating that RPTPs have the capacity for inside-out signaling. Two antagonistically acting families of enzymes regulate phosphorylation of protein tyrosine residues, an important determinant for many cellular functions: protein-tyrosine kinases (PTKs) 1The abbreviations used are: PTKprotein-tyrosine kinaseHAhemagglutininPTPprotein-tyrosine phosphataseEGFRepidermal growth factor receptorHEKhuman embryonic kidneyLARleukocyte common antigen-relatedRPTKreceptor-like PTKRPTPreceptor-like PTPROSreactive oxygen species1The abbreviations used are: PTKprotein-tyrosine kinaseHAhemagglutininPTPprotein-tyrosine phosphataseEGFRepidermal growth factor receptorHEKhuman embryonic kidneyLARleukocyte common antigen-relatedRPTKreceptor-like PTKRPTPreceptor-like PTPROSreactive oxygen species and protein-tyrosine phosphatases (PTPs). PTKs catalyze the phosphorylation of tyrosine residues, and PTPs catalyze the dephosphorylation. The classical PTPs can be subdivided into the cytoplasmic PTPs and the transmembrane PTPs (reviewed in Ref. 1Andersen J.N. Mortensen O.H. Peters G.H. Drake P.G. Iversen L.F. Olsen O.H. Jansen P.G. Andersen H.S. Tonks N.K. Moller N.P. Mol. Cell. Biol. 2001; 21: 7117-7136Crossref PubMed Scopus (593) Google Scholar). Transmembrane PTPs, tentatively called receptor-like PTPs (RPTPs), are interesting because of their potential to signal across the membrane. Besides one transmembrane domain, most RPTPs possess two catalytic domains of which the first contains most of the catalytic activity. The RPTP extracellular domains vary greatly (2Tonks N.K. Neel B.G. Curr. Opin. Cell Biol. 2001; 13: 182-195Crossref PubMed Scopus (462) Google Scholar). Clear evidence for ligands that regulate RPTP activity remains elusive. In some cases, as for the interaction between RPTPβ, leukocyte common antigen-related (LAR), and PTPς and their ligands contactin, laminin/nidogen, and heparan sulfate proteoglycans, respectively, the binding compound is known, but the effect of the ligand on PTP activity needs to be established (3Aricescu A.R. McKinnell I.W. Halfter W. Stoker A.W. Mol. Cell. Biol. 2002; 22: 1881-1892Crossref PubMed Scopus (172) Google Scholar, 4O'Grady P. Thai T.C. Saito H. J. Cell Biol. 1998; 141: 1675-1684Crossref PubMed Scopus (118) Google Scholar, 5Peles E. Nativ M. Campbell P.L. Sakurai T. Martinez R. Lev S. Clary D.O. Schilling J. Barnea G. Plowman G.D. Cell. 1995; 82: 251-260Abstract Full Text PDF PubMed Scopus (368) Google Scholar). Sorby et al. (6Sorby M. Sandstrom J. Ostman A. Oncogene. 2001; 20: 5219-5224Crossref PubMed Scopus (34) Google Scholar) reported an effect of Matrigel on DEP1 activity; however, the exact responsible compound still needs to be established. Only pleiotrophin, a heparin-binding cytokine, was reported to reduce RPTPβ/ζ activity, in that β-catenin phosphorylation was enhanced in cells expressing RPTPβ/ζ in to A. T. W. M. M. S. A. PubMed Scopus Google induced by ligand binding is a for activity. In the of are in with of the dimers are in the active which upon ligand binding and results in and of activity (reviewed in G. T. Curr. Biol. Full Text Full Text PDF PubMed Scopus Google and J. Cell. Full Text Full Text PDF PubMed Scopus Google Scholar). The first evidence for of RPTPs by studies with the RPTP with the extracellular domain of the to the cytoplasmic domain of is by upon ligand binding J. J. A. Cell. Full Text PDF PubMed Scopus Google Scholar). In with is evidence for the of RPTPα by The of evidence that to of the catalytic activity of RPTPα because a of one into the catalytic of the the catalytic site J. T. PubMed Scopus Google Scholar). In activity studies with constitutively mutants In mutants a was in the extracellular domain of RPTPα to the of a disulfide G. J. J. J. J. T. PubMed Scopus Google Scholar). disulfide in whereas with a disulfide similar to the wild type These that of RPTPα to of the catalytic activity the rotational coupling of the dimer is that the of one into the catalytic of the G. J. J. J. J. T. PubMed Scopus Google Scholar). in the of R. T. A. 1998; PubMed Scopus Google Scholar) and dimer mutants of RPTPα G. J. J. J. J. T. PubMed Scopus Google Scholar) the of PTP activity. RPTPs can be by is that RPTPs in G. J. T. Mol. Cell. Biol. 20: PubMed Scopus Google Scholar) and G. J. T. J. Cell Biol. 2001; PubMed Scopus Google Scholar) that RPTPα constitutively forms dimers in forms dimers in as by and S. J. P. A. S. P. J. J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar, A. J. Biol. Full Text PDF PubMed Google Scholar, A. 2002; PubMed Scopus Google Scholar). of of is A. 2002; PubMed Scopus Google of the of coupling to be an important determinant for RPTP activity, and be interesting to rotational coupling in RPTP dimers is studies that the catalytic domain of RPTPα-D2, have a in dimer and we that stress to of in the of inactive dimers J. J. 2002; 21: PubMed Scopus Google Scholar). as shown by H2O2 not induce J. J. 2002; 21: PubMed Scopus Google Scholar). The H2O2-induced conformational change is on the catalytic site in RPTPα-D2, that of the we report that binding to the HA tag the of the of plasma membrane RPTPα the of rotational the tag was in wild type RPTPα and constitutively dimeric, active RPTPα-F135C with a in the extracellular domain, the tag in inactive RPTPα-P137C was that accessibility of the HA tag was on rotational H2O2 induced accessibility of the HA tag in wild type of the tag was on in the extracellular domain and on of RPTPα-D2 and the catalytic site in RPTPα-D2, were required for H2O2-induced HA tag accessibility. results that a conformational change in the cytoplasmic domain of RPTPα to a change in the conformation of the of RPTPα and evidence that RPTPs have the potential for inside-out we report that the conformation of the extracellular domain of RPTPα dimers in to the catalytic of active evidence that the catalytic site in the PTP domain, RPTPα-D2, is required for effect. results that rotational coupling of RPTPα RPTPα an active to an inactive an to accessibility of the tag in the of on to between active and inactive constitutively of RPTPα H2O2 treatment of cells the accessibility of the HA tag in with a of catalytic activity in to H2O2 The effect of H2O2 treatment on the binding of the is on Cys723 in RPTPα-D2 that the conformational change in RPTPα-D2 that we reported J. J. 2002; 21: PubMed Scopus Google Scholar) is The of the extracellular domain was required for of binding to the tag, as shown using mutants with in the extracellular is that of an extracellular domain of residues, which is of a similar to that of the of the tag in whereas the of did to the of the tag are in because of but not the HA tag accessible the that are H2O2-induced accessibility of the tag is and the are similar to H2O2-induced of RPTPα dimers that is required for of In in the that of RPTPα G. J. T. Mol. Cell. Biol. 20: PubMed Scopus Google Scholar) masking of the tag the extracellular domain of did not the RPTPα in we that by of the in RPTPα the tag in the extracellular domain of on we a for the of H2O2 on the conformation of RPTPα dimers In the RPTPα as a active and we have that RPTPα is in the G. J. T. J. Cell Biol. 2001; PubMed Scopus Google Scholar). The that the tag is not accessible in the that most RPTPα is In to a conformational change in RPTPα-D2 to of RPTPα dimers J. J. 2002; 21: PubMed Scopus Google we that H2O2 treatment the conformation of the extracellular domain a active RPTPα-F135C to a inactive results that stress a change in rotational which to the upon of of the extracellular domain of RPTPα remains to be RPTPα and are by their The extracellular domain to the RPTP in the plasma membrane. be a to for has been established by studies with RPTPα and and their cytoplasmic forms J.N. A. R. J. Moller Moller N.P. J. 2001; Scholar) and in studies the effect of of RPTPα and that in the intracellular domain of the RPTPs H. G. A. J. Biol. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). studies with that the RPTPα not as a membrane but to RPTPα J. PubMed Scopus Google conformational change of the as the of a change in conformation of the intracellular domain change binding of RPTPα to its ligands to the extracellular domain of the conformation of the extracellular domain and rotational to a the dimer conformation in the cytoplasmic domain and to of RPTPα activity. ligands have not been reported for Only the protein was reported to to the of RPTPα in J. Cell Biol. PubMed Scopus Google Scholar). of did not accessibility of RPTPα in not results that RPTPα is of a signal cells is a for however, is for signal by (reviewed in Cell Biol. 2002; PubMed Scopus Google and J. T. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). not in to extracellular the of the cells but is the of the cells cellular the conformation of the extracellular domain of their for their results that RPTPs be in a similar is as an important of PTP activity T. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). PTPs have been to be by of their catalytic site A. R. G. G. G. G. G. J. Biol. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; PubMed Scopus Google Scholar, W. H. Cell. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. A. P. J. PubMed Scopus Google Scholar). oxygen species are in to as growth and the of are to PTPs P. T. E. G. G. J. Biol. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, M. T. 1995; PubMed Scopus Google Scholar, J. Biol. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, T.C. T. Tonks N.K. Mol. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). of PTPs by is and that of RPTPα and RPTPs by is not of the catalytic site we that of RPTPα which is responsible for of we a change in the of RPTPα in to of the catalytic site is in cells because of the intracellular The H2O2-induced conformational to the and to RPTPα in an inactive RPTPα but RPTPs be by conformational in the cytoplasmic have shown that H2O2 induced a conformational change in as J. J. J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). be interesting to the conformational change in is by a conformational change of the results that rotational coupling of RPTPα that RPTPα has the capacity for inside-out signaling. be interesting to rotational coupling of RPTPs as Two antagonistically acting families of enzymes regulate phosphorylation of protein tyrosine residues, an important determinant for many cellular functions: protein-tyrosine kinases (PTKs) 1The abbreviations used are: PTKprotein-tyrosine kinaseHAhemagglutininPTPprotein-tyrosine phosphataseEGFRepidermal growth factor receptorHEKhuman embryonic kidneyLARleukocyte common antigen-relatedRPTKreceptor-like PTKRPTPreceptor-like PTPROSreactive oxygen species1The abbreviations used are: PTKprotein-tyrosine kinaseHAhemagglutininPTPprotein-tyrosine phosphataseEGFRepidermal growth factor receptorHEKhuman embryonic kidneyLARleukocyte common antigen-relatedRPTKreceptor-like PTKRPTPreceptor-like PTPROSreactive oxygen species and protein-tyrosine phosphatases (PTPs). PTKs catalyze the phosphorylation of tyrosine residues, and PTPs catalyze the dephosphorylation. The classical PTPs can be subdivided into the cytoplasmic PTPs and the transmembrane PTPs (reviewed in Ref. 1Andersen J.N. Mortensen O.H. Peters G.H. Drake P.G. Iversen L.F. Olsen O.H. Jansen P.G. Andersen H.S. Tonks N.K. Moller N.P. Mol. Cell. Biol. 2001; 21: 7117-7136Crossref PubMed Scopus (593) Google Scholar). Transmembrane PTPs, tentatively called receptor-like PTPs (RPTPs), are interesting because of their potential to signal across the membrane. Besides one transmembrane domain, most RPTPs possess two catalytic domains of which the first contains most of the catalytic activity. The RPTP extracellular domains vary greatly (2Tonks N.K. Neel B.G. Curr. Opin. Cell Biol. 2001; 13: 182-195Crossref PubMed Scopus (462) Google Scholar). Clear evidence for ligands that regulate RPTP activity remains elusive. In some cases, as for the interaction between RPTPβ, leukocyte common antigen-related (LAR), and PTPς and their ligands contactin, laminin/nidogen, and heparan sulfate proteoglycans, respectively, the binding compound is known, but the effect of the ligand on PTP activity needs to be established (3Aricescu A.R. McKinnell I.W. Halfter W. Stoker A.W. Mol. Cell. Biol. 2002; 22: 1881-1892Crossref PubMed Scopus (172) Google Scholar, 4O'Grady P. Thai T.C. Saito H. J. Cell Biol. 1998; 141: 1675-1684Crossref PubMed Scopus (118) Google Scholar, 5Peles E. Nativ M. Campbell P.L. Sakurai T. Martinez R. Lev S. Clary D.O. Schilling J. Barnea G. Plowman G.D. Cell. 1995; 82: 251-260Abstract Full Text PDF PubMed Scopus (368) Google Scholar). Sorby et al. (6Sorby M. Sandstrom J. Ostman A. Oncogene. 2001; 20: 5219-5224Crossref PubMed Scopus (34) Google Scholar) reported an effect of Matrigel on DEP1 activity; however, the exact responsible compound still needs to be established. Only pleiotrophin, a heparin-binding cytokine, was reported to reduce RPTPβ/ζ activity, in that β-catenin phosphorylation was enhanced in cells expressing RPTPβ/ζ in to A. T. W. M. M. S. A. PubMed Scopus Google Scholar). protein-tyrosine hemagglutinin protein-tyrosine phosphatase growth factor embryonic leukocyte common antigen-related receptor-like receptor-like PTP oxygen species protein-tyrosine hemagglutinin protein-tyrosine phosphatase growth factor embryonic leukocyte common antigen-related receptor-like receptor-like PTP oxygen species Dimerization induced by ligand binding is a for activity. In the of are in with of the dimers are in the active which upon ligand binding and results in and of activity (reviewed in G. T. Curr. Biol. Full Text Full Text PDF PubMed Scopus Google and J. Cell. Full Text Full Text PDF PubMed Scopus Google Scholar). The first evidence for of RPTPs by studies with the RPTP with the extracellular domain of the to the cytoplasmic domain of is by upon ligand binding J. J. A. Cell. Full Text PDF PubMed Scopus Google Scholar). In with is evidence for the of RPTPα by The of evidence that to of the catalytic activity of RPTPα because a of one into the catalytic of the the catalytic site J. T. PubMed Scopus Google Scholar). In activity studies with constitutively mutants In mutants a was in the extracellular domain of RPTPα to the of a disulfide G. J. J. J. J. T. PubMed Scopus Google Scholar). disulfide in whereas with a disulfide similar to the wild type These that of RPTPα to of the catalytic activity the rotational coupling of the dimer is that the of one into the catalytic of the G. J. J. J. J. T. PubMed Scopus Google Scholar). in the of R. T. A. 1998; PubMed Scopus Google Scholar) and dimer mutants of RPTPα G. J. J. J. J. T. PubMed Scopus Google Scholar) the of PTP activity. RPTPs can be by is that RPTPs in G. J. T. Mol. Cell. Biol. 20: PubMed Scopus Google Scholar) and G. J. T. J. Cell Biol. 2001; PubMed Scopus Google Scholar) that RPTPα constitutively forms dimers in forms dimers in as by and S. J. P. A. S. P. J. J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar, A. J. Biol. Full Text PDF PubMed Google Scholar, A. 2002; PubMed Scopus Google Scholar). of of is A. 2002; PubMed Scopus Google of the of coupling to be an important determinant for RPTP activity, and be interesting to rotational coupling in RPTP dimers is studies that the catalytic domain of RPTPα-D2, have a in dimer and we that stress to of in the of inactive dimers J. J. 2002; 21: PubMed Scopus Google Scholar). as shown by H2O2 not induce J. J. 2002; 21: PubMed Scopus Google Scholar). The H2O2-induced conformational change is on the catalytic site in RPTPα-D2, that of the Here we report that binding to the HA tag the of the of plasma membrane RPTPα the of rotational the tag was in wild type RPTPα and constitutively dimeric, active RPTPα-F135C with a in the extracellular domain, the tag in inactive RPTPα-P137C was that accessibility of the HA tag was on rotational H2O2 induced accessibility of the HA tag in wild type of the tag was on in the extracellular domain and on of RPTPα-D2 and the catalytic site in RPTPα-D2, were required for H2O2-induced HA tag accessibility. results that a conformational change in the cytoplasmic domain of RPTPα to a change in the conformation of the of RPTPα and evidence that RPTPs have the potential for inside-out signaling. we report that the conformation of the extracellular domain of RPTPα dimers in to the catalytic of active evidence that the catalytic site in the PTP domain, RPTPα-D2, is required for effect. results that rotational coupling of RPTPα RPTPα an active to an inactive an to accessibility of the tag in the of on to between active and inactive constitutively of RPTPα H2O2 treatment of cells the accessibility of the HA tag in with a of catalytic activity in to H2O2 The effect of H2O2 treatment on the binding of the is on Cys723 in RPTPα-D2 that the conformational change in RPTPα-D2 that we reported J. J. 2002; 21: PubMed Scopus Google Scholar) is The of the extracellular domain was required for of binding to the tag, as shown using mutants with in the extracellular is that of an extracellular domain of residues, which is of a similar to that of the of the tag in whereas the of did to the of the tag are in because of but not the HA tag accessible the that are H2O2-induced accessibility of the tag is and the are similar to H2O2-induced of RPTPα dimers that is required for of In in the that of RPTPα G. J. T. Mol. Cell. Biol. 20: PubMed Scopus Google Scholar) masking of the tag the extracellular domain of did not the RPTPα in we that by of the in RPTPα the tag in the extracellular domain of on we a for the of H2O2 on the conformation of RPTPα dimers In the RPTPα as a active and we have that RPTPα is in the G. J. T. J. Cell Biol. 2001; PubMed Scopus Google Scholar). The that the tag is not accessible in the that most RPTPα is In to a conformational change in RPTPα-D2 to of RPTPα dimers J. J. 2002; 21: PubMed Scopus Google we that H2O2 treatment the conformation of the extracellular domain a active RPTPα-F135C to a inactive results that stress a change in rotational which to the upon of of the extracellular domain of RPTPα remains to be RPTPα and are by their The extracellular domain to the RPTP in the plasma membrane. be a to for has been established by studies with RPTPα and and their cytoplasmic forms J.N. A. R. J. Moller Moller N.P. J. 2001; Scholar) and in studies the effect of of RPTPα and that in the intracellular domain of the RPTPs H. G. A. J. Biol. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). studies with that the RPTPα not as a membrane but to RPTPα J. PubMed Scopus Google conformational change of the as the of a change in conformation of the intracellular domain change binding of RPTPα to its ligands to the extracellular domain of the conformation of the extracellular domain and rotational to a the dimer conformation in the cytoplasmic domain and to of RPTPα activity. ligands have not been reported for Only the protein was reported to to the of RPTPα in J. Cell Biol. PubMed Scopus Google Scholar). of did not accessibility of RPTPα in not results that RPTPα is of a signal cells is a for however, is for signal by (reviewed in Cell Biol. 2002; PubMed Scopus Google and J. T. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). not in to extracellular the of the cells but is the of the cells cellular the conformation of the extracellular domain of their for their results that RPTPs be in a similar is as an important of PTP activity T. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). PTPs have been to be by of their catalytic site A. R. G. G. G. G. G. J. Biol. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; PubMed Scopus Google Scholar, W. H. Cell. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. A. P. J. PubMed Scopus Google Scholar). oxygen species are in to as growth and the of are to PTPs P. T. E. G. G. J. Biol. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, M. T. 1995; PubMed Scopus Google Scholar, J. Biol. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, T.C. T. Tonks N.K. Mol. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). of PTPs by is and that of RPTPα and RPTPs by is not of the catalytic site we that of RPTPα which is responsible for of we a change in the of RPTPα in to of the catalytic site is in cells because of the intracellular The H2O2-induced conformational to the and to RPTPα in an inactive RPTPα but RPTPs be by conformational in the cytoplasmic have shown that H2O2 induced a conformational change in as J. J. J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). be interesting to the conformational change in is by a conformational change of the results that rotational coupling of RPTPα that RPTPα has the capacity for inside-out signaling. be interesting to rotational coupling of RPTPs as Here we report that the conformation of the extracellular domain of RPTPα dimers in to the catalytic of active evidence that the catalytic site in the PTP domain, RPTPα-D2, is required for effect. results that rotational coupling of RPTPα RPTPα an active to an inactive an to accessibility of the tag in the of on to between active and inactive constitutively of RPTPα H2O2 treatment of cells the accessibility of the HA tag in with a of catalytic activity in to H2O2 The effect of H2O2 treatment on the binding of the is on Cys723 in RPTPα-D2 that the conformational change in RPTPα-D2 that we reported J. J. 2002; 21: PubMed Scopus Google Scholar) is The of the extracellular domain was required for of binding to the tag, as shown using mutants with in the extracellular is that of an extracellular domain of residues, which is of a similar to that of the of the tag in whereas the of did to the of the tag are in because of but not the HA tag accessible the that are H2O2-induced accessibility of the tag is and the are similar to H2O2-induced of RPTPα dimers that is required for of In in the that of RPTPα G. J. T. Mol. Cell. Biol. 20: PubMed Scopus Google Scholar) masking of the tag the extracellular domain of did not the RPTPα in we that by of the in RPTPα the tag in the extracellular domain of on we a for the of H2O2 on the conformation of RPTPα dimers In the RPTPα as a active and we have that RPTPα is in the G. J. T. J. Cell Biol. 2001; PubMed Scopus Google Scholar). The that the tag is not accessible in the that most RPTPα is In to a conformational change in RPTPα-D2 to of RPTPα dimers J. J. 2002; 21: PubMed Scopus Google we that H2O2 treatment the conformation of the extracellular domain a active RPTPα-F135C to a inactive results that stress a change in rotational which to the upon of The of the extracellular domain of RPTPα remains to be RPTPα and are by their The extracellular domain to the RPTP in the plasma membrane. be a to for has been established by studies with RPTPα and and their cytoplasmic forms J.N. A. R. J. Moller Moller N.P. J. 2001; Scholar) and in studies the effect of of RPTPα and that in the intracellular domain of the RPTPs H. G. A. J. Biol. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). studies with that the RPTPα not as a membrane but to RPTPα J. PubMed Scopus Google Scholar). conformational change of the as the of a change in conformation of the intracellular domain change binding of RPTPα to its ligands to the extracellular domain of the conformation of the extracellular domain and rotational to a the dimer conformation in the cytoplasmic domain and to of RPTPα activity. ligands have not been reported for Only the protein was reported to to the of RPTPα in J. Cell Biol. PubMed Scopus Google Scholar). of did not accessibility of RPTPα in not results that RPTPα is of a signal cells is a for however, is for signal by (reviewed in Cell Biol. 2002; PubMed Scopus Google and J. T. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). not in to extracellular the of the cells but is the of the cells cellular the conformation of the extracellular domain of their for their results that RPTPs be in a similar is as an important of PTP activity T. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). PTPs have been to be by of their catalytic site A. R. G. G. G. G. G. J. Biol. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; PubMed Scopus Google Scholar, W. H. Cell. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. A. P. J. PubMed Scopus Google Scholar). oxygen species are in to as growth and the of are to PTPs P. T. E. G. G. J. Biol. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, M. T. 1995; PubMed Scopus Google Scholar, J. Biol. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, T.C. T. Tonks N.K. Mol. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). of PTPs by is and that of RPTPα and RPTPs by is not of the catalytic site we that of RPTPα which is responsible for of we a change in the of RPTPα in to of the catalytic site is in cells because of the intracellular The H2O2-induced conformational to the and to RPTPα in an inactive RPTPα but RPTPs be by conformational in the cytoplasmic have shown that H2O2 induced a conformational change in as J. J. J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). be interesting to the conformational change in is by a conformational change of the results that rotational coupling of RPTPα that RPTPα has the capacity for inside-out signaling. be interesting to rotational coupling of RPTPs as for the and for the