Delineation of Type I Protein Kinase A-selective Signaling Events Using an RI Anchoring Disruptor

Abstract

Control of specificity in cAMP signaling is achieved by A-kinase anchoring proteins (AKAPs), which assemble cAMP effectors such as protein kinase A (PKA) into multiprotein signaling complexes in the cell. AKAPs tether the PKA holoenzymes at subcellular locations to favor the phosphorylation of selected substrates. PKA anchoring is mediated by an amphipathic helix of 14-18 residues on each AKAP that binds to the R subunit dimer of the PKA holoenzymes. Using a combination of bioinformatics and peptide array screening, we have developed a high affinity-binding peptide called RIAD (RIanchoring disruptor) with >1000-fold selectivity for type I PKA over type II PKA. Cell-soluble RIAD selectively uncouples cAMP-mediated inhibition of T cell function and inhibits progesterone synthesis at the mitochondria in steroid-producing cells. This study suggests that these processes are controlled by the type I PKA holoenzyme and that RIAD can be used as a tool to define anchored type I PKA signaling events. Control of specificity in cAMP signaling is achieved by A-kinase anchoring proteins (AKAPs), which assemble cAMP effectors such as protein kinase A (PKA) into multiprotein signaling complexes in the cell. AKAPs tether the PKA holoenzymes at subcellular locations to favor the phosphorylation of selected substrates. PKA anchoring is mediated by an amphipathic helix of 14-18 residues on each AKAP that binds to the R subunit dimer of the PKA holoenzymes. Using a combination of bioinformatics and peptide array screening, we have developed a high affinity-binding peptide called RIAD (RIanchoring disruptor) with >1000-fold selectivity for type I PKA over type II PKA. Cell-soluble RIAD selectively uncouples cAMP-mediated inhibition of T cell function and inhibits progesterone synthesis at the mitochondria in steroid-producing cells. This study suggests that these processes are controlled by the type I PKA holoenzyme and that RIAD can be used as a tool to define anchored type I PKA signaling events. The cAMP signaling pathway synchronizes a variety of physiological responses including cell proliferation and differentiation, microtubule dynamics, reproductive function, modulation of immune responses, and steroidogenesis (1Carnegie G.K. Smith F.D. McConnachie G. Langeberg L.K. Scott J.D. Mol. Cell. 2004; 15: 889-899Abstract Full Text Full Text PDF PubMed Scopus (130) Google Scholar, 2Klauck T.M. Faux M.C. Labudda K. Langeberg L.K. Jaken S. Scott J.D. Science. 1996; 271: 1589-1592Crossref PubMed Scopus (480) Google Scholar, 3Tasken K. Aandahl E.M. Physiol. Rev. 2004; 84: 137-167Crossref PubMed Scopus (620) Google Scholar). Many of these responses require activation of the cAMP-dependent protein kinase (PKA). 3The abbreviations used are: PKA, protein kinase A; RIAD, RI anchoring disruptor; scRIAD, scrambled RIAD; AKAP, A-kinase anchoring protein; cAMP, cyclic AMP; PDSM, position-dependent scoring matrix; PKI, protein kinase inhibitor; AMPA, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid; ACTH, adrenocorticotropic hormone; StAR, steroid acute response protein, LAT, linker for activation of T cells; Csk, C-terminal Src kinase; Lck, lymphocyte-specific protein-tyrosine kinase; GFP, green fluorescent protein; HEK, human embryonic kidney. 3The abbreviations used are: PKA, protein kinase A; RIAD, RI anchoring disruptor; scRIAD, scrambled RIAD; AKAP, A-kinase anchoring protein; cAMP, cyclic AMP; PDSM, position-dependent scoring matrix; PKI, protein kinase inhibitor; AMPA, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid; ACTH, adrenocorticotropic hormone; StAR, steroid acute response protein, LAT, linker for activation of T cells; Csk, C-terminal Src kinase; Lck, lymphocyte-specific protein-tyrosine kinase; GFP, green fluorescent protein; HEK, human embryonic kidney.The dormant PKA holoenzyme is a heterotetramer composed of two catalytic (C) subunits held in an inactive conformation by a regulatory (R) subunit dimer. Upon activation with cAMP, the C subunits are released from their interaction with the R subunit dimer and are free to phosphorylate a plethora of target substrates. Individual cells express a range of PKA isozymes differing in R (RIα,RIβ, RIIα, RIIβ) and C(Cα,Cβ,Cγ) subunit composition. The type I and type II PKA isozymes, which are classified on the basis of their R subunit dimer, possess slightly different physical and biological properties including a differential sensitivity to cAMP. Spatiotemporal regulation of PKA phosphorylation events is facilitated by A-kinase anchoring proteins (AKAPs). This family of structurally diverse but functionally related proteins act as molecular scaffolds to cluster PKA with specific substrates and signal termination enzymes such as phosphatases (4Alto N. Michel J.J.C. Dodge K.L. Langeberg L.K. Scott J.D. Diabetes. 2002; 51: 385-388Crossref PubMed Google Scholar, 5Coghlan V.M. Perrino B.A. Howard M. Langeberg L.K. Hicks J.B. Gallatin W.M. Scott J.D. Science. 1995; 267: 108-111Crossref PubMed Scopus (525) Google Scholar) and cAMP-specific phosphodiesterases (6Baillie G.S. Scott J.D. Houslay M.D. FEBS Lett. 2005; 579: 3264-3270Crossref PubMed Scopus (179) Google Scholar, 7Dodge-Kafka K.L. Soughayer J. Pare G.C. Michel J.J.C. Langeberg L.K. Kapiloff M.S. Scott J.D. Nature. 2005; 437: 574-578Crossref PubMed Scopus (435) Google Scholar, 8Dodge K.L. Khouangsathiene S. Kapiloff M.S. Mouton R. Hill E.V. Houslay M.D. Langeberg L.K. Scott J.D. EMBO J. 2001; 20: 1921-1930Crossref PubMed Scopus (398) Google Scholar, 9Tasken K.A. Collas P. Kemmners W.A. Witczak O. Conti M. Tasken K. J. Biol. Chem. 2001; 276: 21999-22002Abstract Full Text Full Text PDF PubMed Scopus (203) Google Scholar). The number of AKAPs has been estimated to more than 75, of which ∼50 have been identified to date (3Tasken K. Aandahl E.M. Physiol. Rev. 2004; 84: 137-167Crossref PubMed Scopus (620) Google Scholar, 10Wong W. Scott J.D. Nat. Rev. Mol. Cell Biol. 2004; 5: 959-970Crossref PubMed Scopus (848) Google Scholar). Although the majority of AKAPs described to date bind type II PKA via the RII regulatory subunit, several dual function AKAPs are capable of interacting with both the type I and the type II PKA holoenzyme (11Huang L.J.S. Durick K. Weiner J.A. Chun J. Taylor S.S. J. Biol. Chem. 1997; 272: 8057-8064Abstract Full Text Full Text PDF PubMed Scopus (257) Google Scholar, 12Wang L. Sunahara R.K. Krumins A. Perkins G. Crochiere M.L. Mackey M. Bell S. Ellisman M.H. Taylor S.S. Proc. Natl. Acad. Sci. U. S. A. 2001; 98: 3220-3225Crossref PubMed Scopus (88) Google Scholar, 13Carrera A. Gerton G.L. Moss S.B. Dev. Biol. 1994; 165: 272-284Crossref PubMed Scopus (186) Google Scholar, 14Miki E. Eddy E.M. J. Biol. Chem. 1998; 273: 34384-34390Abstract Full Text Full Text PDF PubMed Scopus (84) Google Scholar, 15Li H.W. Adamik R. Pacheco-Rodriguez G. Moss J. Vaughan M. Proc. Natl. Acad. Sci. U. S. A. 2003; 100: 1627-1632Crossref PubMed Scopus (69) Google Scholar). There are also examples of anchoring proteins such as AKAPce (16Angelo R. Rubin C.S. J. Biol. Chem. 1998; 273: 14633-14643Abstract Full Text Full Text PDF PubMed Scopus (91) Google Scholar), PAP7 (17Li H. Degenhardt B. Tobin D. Yao Z.X. Tasken K. Papadopoulos V. Mol. Endocrinol. 2001; 15: 2211-2228Crossref PubMed Scopus (139) Google Scholar), and merlin (18Gronholm M. Vossebein L. Carlson C.R. Kuja-Panula J. Teesalu T. Alfthan K. Vaheri A. Rauvala H. Herberg F.W. Tasken K. Carpen O. J. Biol. Chem. 2003; 278: 41167-41172Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar) that selectively interact with the RI subunit of PKA. The molecular basis for PKA anchoring is the interaction of an amphipathic helical motif of 14-18 residues on the AKAP with a hydrophobic groove in the N-terminal dimerization domain of the R subunit. High affinity peptides mimicking the amphipathic helix bind to the R dimer and can serve as competitive inhibitors of the PKA-AKAP interaction and inhibit signaling by delocalization of PKA. The prototypic inhibitor that has been used to disrupt PKA localization is the peptide known as Ht31 (19Carr D.W. Hausken Z.E. Fraser I.D.C. Stofkohahn R.E. Scott J.D. J. Biol. Chem. 1992; 267: 13376-13382Abstract Full Text PDF PubMed Google Scholar), which encompasses the RII binding domain of human thyroid AKAP (AKAP-Lbc) (20Diviani D. Soderling J. Scott J.D. J. Biol. Chem. 2001; 276: 44247-44257Abstract Full Text Full Text PDF PubMed Scopus (203) Google Scholar). Recently, the dual specificity anchoring protein D-AKAP2 has been used as a template to design peptides that preferentially interact with RIα in vitro (21Burns-Hamuro L.L. Ma Y.L. Kammerer S. Reineke U. Self C. Cook C. Olson G.L. Cantor C.R. Braun A. Taylor S.S. Proc. Natl. Acad. Sci. U. S. A. 2003; 100: 4072-4077Crossref PubMed Scopus (118) Google Scholar). Here, we have conducted a bioinformatics analysis on a set of dual-affinity AKAP binding sequences to develop a peptide that binds RIα with higher affinity and specificity than any naturally occurring AKAP or other RIα-binding peptide reported. When introduced into cells, this peptide specifically disrupts anchoring of type I PKA from intracellular locations and inhibits type I PKA regulation of T cell effector function and steroid biosynthesis. Autospot Peptide Array—Peptide arrays were synthesized on cellulose paper using an Autospot Robot ASP222 or a Multipep automated peptide synthesizer (INTAVIS Bioanalytical Instruments AG) as described (22Frank R. Tetrahedron. 1992; 48: 9217-9232Crossref Scopus (920) Google Scholar). MEME used for C. Proc. Mol. Biol. 1994; Google Scholar). MEME motif and a motif of and and were used analysis using or were conducted as described using Z.E. V.M. Scott J.D. Mol. Biol. 1998; Google Scholar) or or human RIα or by by the with RIα at and the in with for at RIα by with an RIα and with the sequences were into the and of and are The in or human RIα type into using a RIα RIα and RIα were by and into were by RIAD and peptides were with of RIα or for in with on a binding were with were from the from of Cell T cells were by as described E.M. P. S.S. V. Tasken K. J. 1998; PubMed Scopus Google Scholar). embryonic cells and cells were in or with and in a of and by at than and PKA cells at were with of fluorescent protein and using the were in and with inhibitors were in and PKA kinase were by the paper J.D. E.M. PubMed Scopus Google Scholar). The protein kinase inhibitor residues peptide used as a specific inhibitor of the kinase J.D. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar). and were with PKA RIIα, and C or for activation of T cells; and or used as a RIα and K.A. Collas P. Kemmners W.A. Witczak O. Conti M. Tasken K. J. Biol. Chem. 2001; 276: 21999-22002Abstract Full Text Full Text PDF PubMed Scopus (203) Google or and were on T cells or cells to or were with which in and on cells at for cell cells were in with and using were in with and were used at a in with and for using at a of were using a and RIα or in by and with cAMP as described F.W. A. T. Vossebein L. Tasken K. J. Mol. Biol. PubMed Scopus Google Scholar). by the using protein Peptide and and were synthesized or with residues at the C and to or in The peptides were to the cell at different The peptide used were by were using a as described D. T. J. 2004; PubMed Scopus Google Scholar). cells were in at a of cells the of StAR, the cells were with for peptide The cells were with the peptide for with for and with or for from were and progesterone were by or the from cells were at with RIAD and peptides synthesized on The were for in and and in high in of as described B. Tasken K. Carlson C.R. J. 2005; PubMed Scopus Google Scholar). were with an and and were a controlled by a The were by a of at were and by using were at and at analysis of with using of an RIα an to define an and specific peptide for type I PKA, we used the MEME to the R binding from several anchoring proteins that interact with RIα C. Proc. Mol. Biol. 1994; Google Scholar). This for of and the to a on the basis of to in the proteins in a The R binding sequences from (11Huang L.J.S. Durick K. Weiner J.A. Chun J. Taylor S.S. J. Biol. Chem. 1997; 272: 8057-8064Abstract Full Text Full Text PDF PubMed Scopus (257) Google Scholar), G. M. C. 1996; PubMed Scopus Google Scholar), M. E. M. D. C. R. H. W. O. and K. for and and A. Gerton G.L. Moss S.B. Dev. Biol. 1994; 165: 272-284Crossref PubMed Scopus (186) Google Scholar, 14Miki E. Eddy E.M. J. Biol. Chem. 1998; 273: 34384-34390Abstract Full Text Full Text PDF PubMed Scopus (84) Google Scholar) were and by this A position-dependent scoring of identified of this using peptide arrays and binding of RIα to the peptides using RIα a R subunit that can be by the C subunit of PKA in vitro S. Taylor S.S. J. Biol. Chem. Full Text PDF PubMed Google Scholar). of RIα binding with the and other peptides by A of peptide from both the and C to the RIα binding to an peptide This RIα more than the AKAP peptide sequences Although we were to an RIα binding the the to bind as by the binding of the RIα and of of the to for RI by a peptide array using RIα as a peptide were with at each and binding were by A and The binding of each peptide with that of peptides of the with we that of or of hydrophobic RIα and of or at the RIα binding and peptides that to in and the RIα binding of the over in A and This in a of peptide arrays and peptides were for interaction with RIα of used to the RIα and binding of each were to a peptide that a high affinity for RIα but bind to This peptide a in RIα binding affinity over the and an selectivity for RIα over this RIα-binding peptide RI anchoring as of RIAD in of RIAD and by and in the of which and RIAD and for peptides with helical of and RIAD to residues which used in described a of in the RIAD on a helical that of hydrophobic and a When this is with peptide array suggests that in the hydrophobic are for R subunit in are to high affinity interaction with RIAD and a peptide with a scrambled were synthesized with and used in to the of RIAD for both R for RIAD interaction with RIα to be to RIAD with a of Control that the peptide affinity for RI or RII RIAD a for RIα over This suggests that RIAD is more for RIα than a peptide from the dual specificity anchoring protein (21Burns-Hamuro L.L. Ma Y.L. Kammerer S. Reineke U. Self C. Cook C. Olson G.L. Cantor C.R. Braun A. Taylor S.S. Proc. Natl. Acad. Sci. U. S. A. 2003; 100: 4072-4077Crossref PubMed Scopus (118) Google Scholar). RIAD with affinity to human and RIα as by the of variety of used to the interaction of RIAD with the type I PKA in cells. RIAD or to the were into cells from cells were to and used for an RIα The RIAD with high affinity to RIα the RIα RIAD with a higher that the RIα has a more AKAP binding Control that bind to protein PKA binds to RIAD, with an RIα were from cells. with RIα Control using an RII were of proteins were in the immune complexes as by with PKA with but with as in an in vitro kinase using as PKA higher in the than in the with with the which is to bind PKA. Control that of the kinase by the V.M. Perrino B.A. Howard M. Langeberg L.K. Hicks J.B. Gallatin W.M. Scott J.D. Science. 1995; 267: 108-111Crossref PubMed Scopus (525) Google Scholar, G.S. Scott J.D. Houslay M.D. FEBS Lett. 2005; 579: 3264-3270Crossref PubMed Scopus (179) Google Scholar, 7Dodge-Kafka K.L. Soughayer J. Pare G.C. Michel J.J.C. Langeberg L.K. Kapiloff M.S. Scott J.D. Nature. 2005; 437: 574-578Crossref PubMed Scopus (435) Google Scholar, 8Dodge K.L. Khouangsathiene S. Kapiloff M.S. Mouton R. Hill E.V. Houslay M.D. Langeberg L.K. Scott J.D. EMBO J. 2001; 20: 1921-1930Crossref PubMed Scopus (398) Google Scholar, 9Tasken K.A. Collas P. Kemmners W.A. Witczak O. Conti M. Tasken K. J. Biol. Chem. 2001; 276: 21999-22002Abstract Full Text Full Text PDF PubMed Scopus (203) Google Scholar, 10Wong W. Scott J.D. Nat. Rev. Mol. Cell Biol. 2004; 5: 959-970Crossref PubMed Scopus (848) Google Scholar, L.J.S. Durick K. Weiner J.A. Chun J. Taylor S.S. J. Biol. Chem. 1997; 272: 8057-8064Abstract Full Text Full Text PDF PubMed Scopus (257) Google Scholar, 12Wang L. Sunahara R.K. Krumins A. Perkins G. Crochiere M.L. Mackey M. Bell S. Ellisman M.H. Taylor S.S. Proc. Natl. Acad. Sci. U. S. A. 2001; 98: 3220-3225Crossref PubMed Scopus (88) Google Scholar, 13Carrera A. Gerton G.L. Moss S.B. Dev. Biol. 1994; 165: 272-284Crossref PubMed Scopus (186) Google Scholar, 14Miki E. Eddy E.M. J. Biol. Chem. 1998; 273: 34384-34390Abstract Full Text Full Text PDF PubMed Scopus (84) Google Scholar, 15Li H.W. Adamik R. Pacheco-Rodriguez G. Moss J. Vaughan M. Proc. Natl. Acad. Sci. U. S. A. 2003; 100: 1627-1632Crossref PubMed Scopus (69) Google Scholar, R. Rubin C.S. J. Biol. Chem. 1998; 273: 14633-14643Abstract Full Text Full Text PDF PubMed Scopus (91) Google Scholar, H. Degenhardt B. Tobin D. Yao Z.X. Tasken K. Papadopoulos V. Mol. Endocrinol. 2001; 15: 2211-2228Crossref PubMed Scopus (139) Google Scholar, M. Vossebein L. Carlson C.R. Kuja-Panula J. Teesalu T. Alfthan K. Vaheri A. Rauvala H. Herberg F.W. Tasken K. Carpen O. J. Biol. Chem. 2003; 278: 41167-41172Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar, D.W. Hausken Z.E. Fraser I.D.C. Stofkohahn R.E. Scott J.D. J. Biol. Chem. 1992; 267: 13376-13382Abstract Full Text PDF PubMed Google Scholar, D. Soderling J. Scott J.D. J. Biol. Chem. 2001; 276: 44247-44257Abstract Full Text Full Text PDF PubMed Scopus (203) Google Scholar, L.L. Ma Y.L. Kammerer S. Reineke U. Self C. Cook C. Olson G.L. Cantor C.R. Braun A. Taylor S.S. Proc. Natl. Acad. Sci. U. S. A. 2003; 100: 4072-4077Crossref PubMed Scopus (118) Google Scholar, R. Tetrahedron. 1992; 48: 9217-9232Crossref Scopus (920) Google Scholar, C. Proc. Mol. Biol. 1994; Google Scholar, Z.E. V.M. Scott J.D. Mol. Biol. 1998; Google Scholar) a specific inhibitor of PKA the in that RIAD with type I PKA cells. RIAD II the of that RIAD is a that disrupts type I PKA anchoring cells. this we of RIAD any on signaling events to be mediated by type II PKA A is the of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic in the of which an anchored of type II PKA as by anchoring using the Ht31 anchoring peptide C. D.W. G. Scott J.D. G.L. Nature. 1994; PubMed Scopus Google Scholar). a to the of the different peptides the A that of peptide or an RII specific peptide G. B. P. N. G. K. J. D. and D. for in a in the A and of RIAD the the RIAD to a PKA type II signaling of T Cell by that RIAD to to type II PKA, to this peptide anchored signaling events that are mediated by type I PKA. T cell function is by cAMP E.M. T. T. Tasken K. J. 2002; PubMed Scopus (88) Google Scholar, V. T. T. J. Biol. Chem. 1992; 267: Full Text PDF PubMed Google Scholar, Tasken K. V. T. T. Science. 1994; PubMed Scopus Google Scholar), which a that type I PKA phosphorylation and activation of the C-terminal Src kinase H. T. Tasken K. J. Biol. Chem. 2003; 278: Full Text Full Text PDF PubMed Scopus Google Scholar, T. H. S. V. B. B. T. Tasken K. J. Biol. Chem. 2001; 276: Full Text Full Text PDF PubMed Scopus Google Scholar, T. V. M. V. T. Tasken K. J. 2001; PubMed Scopus Google Scholar, T. H. S. V. Tasken K. J. Biol. Chem. 2003; 278: Full Text Full Text PDF PubMed Scopus Google Scholar). in a in the C of which inhibits and to of T cell signaling to the T. Tasken K. J. 2003; PubMed Scopus Google Scholar). cAMP-mediated inhibition of T cell function is to require anchoring of type I PKA to the RI AKAP, we to of PKA anchoring by RIAD these events. RIAD and were by residues to the C of the peptides and of and from the cell of T cells as by of from the O. G. M. Tasken K. T. S. EMBO J. PubMed Scopus Google Scholar) Control that peptide on PKA localization in these cells. from T cells by were for of PKA. cells with of were by and in of were of were LAT, an protein in S. Tasken K. J.B. J. 1998; PubMed Scopus Google Scholar, J. J. Cell. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar), used as an the of RIAD on cAMP regulation of T cell function, the phosphorylation of in When cells were with to the a in the of phosphorylation in and phosphorylation were than the cells were with with cells with or cells of type I PKA from by RIAD the pathway in T cells. the regulation of T cell function by type I PKA signaling can be by RIAD of by in steroid is the of to by the Rev. 2001; PubMed Scopus Google Scholar, Rev. Physiol. 2001; PubMed Scopus Google Scholar). The is in the and the of from the by the This is facilitated by the steroid acute response protein which is a PKA phosphorylation is a for acute regulation of steroid by adrenocorticotropic or in cells and cells, J. H. Papadopoulos V. J. Mol. Biol. 2003; PubMed Scopus Google Scholar, Biol. 2005; PubMed Scopus Google Scholar). I PKA anchoring to the mitochondria via interaction with PAP7 is to be for this regulation (17Li H. Degenhardt B. Tobin D. Yao Z.X. Tasken K. Papadopoulos V. Mol. Endocrinol. 2001; 15: 2211-2228Crossref PubMed Scopus (139) Google Scholar). this we or to cells. cells with RIα from as by the of RIα and a in cells with to as by the of the RIα signal with were also used to the interaction of RIAD with the type I PKA in cell Cell were with RIAD or The were and proteins were from the analysis of the that RIAD to RIα and the C subunit of PKA but of the PKA subunits with the peptide RIAD selectively with type I PKA holoenzyme in cells and can be used to selectively disrupt the of this kinase in these cells. the of type I anchoring on phosphorylation of and on steroid we at the protein were by cAMP and and this in cells the of on PKA phosphorylation of StAR, used to protein synthesis and and of cells with or in the of the peptide cells been by the progesterone were in the of the of progesterone with cells with or or cells with the the of phosphorylation progesterone to and the inhibition that the PKA phosphorylation in H. J. Biol. Chem. 1997; 272: Full Text Full Text PDF PubMed Scopus Google Scholar). When that type I anchoring is for regulation of steroid at the of Here, we the of the anchoring RIAD, an peptide that a of selectivity of binding to type I PKA over type II PKA. RIAD binds type I with a higher affinity than any AKAP or other anchoring peptides The affinity of RIAD for RIα is than (21Burns-Hamuro L.L. Ma Y.L. Kammerer S. Reineke U. Self C. Cook C. Olson G.L. Cantor C.R. Braun A. Taylor S.S. Proc. Natl. Acad. Sci. U. S. A. 2003; 100: 4072-4077Crossref PubMed Scopus (118) Google Scholar) and more with RIAD has a higher RIα affinity and is K. and C. R. more RIAD has over in cAMP signaling events that on anchoring of type I PKA. RIAD from a high affinity RIα binding on R binding sequences from the dual affinity (11Huang L.J.S. Durick K. Weiner J.A. Chun J. Taylor S.S. J. Biol. Chem. 1997; 272: 8057-8064Abstract Full Text Full Text PDF PubMed Scopus (257) Google Scholar), G. M. C. 1996; PubMed Scopus Google Scholar), and and A. Gerton G.L. Moss S.B. Dev. Biol. 1994; 165: 272-284Crossref PubMed Scopus (186) Google Scholar, 14Miki E. Eddy E.M. J. Biol. Chem. 1998; 273: 34384-34390Abstract Full Text Full Text PDF PubMed Scopus (84) Google Scholar). sequences from other of RIα binding were to RIα affinity and of the by peptide arrays identified that are for high RIα and into specific in the The of is with the in of RIα P. M. S. Taylor S.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar) with the more hydrophobic of of the be to the in AKAP binding for type I type II PKA. sequences to the and and into the cells with S. Rev. 2005; PubMed Scopus Google Scholar). The selectivity of RIAD for type I PKA in two biological RIAD on type II in but type I inhibition of T cell function by anchored type I PKA from which phosphorylation of and T cell Peptide and cAMP are known to steroid biosynthesis. steroidogenesis be by or cAMP in a type I cell M.S. G.S. 1992; PubMed Scopus Google Scholar). PAP7 has been described to be in steroidogenesis by anchoring type I PKA with the in mitochondria (17Li H. Degenhardt B. Tobin D. Yao Z.X. Tasken K. Papadopoulos V. Mol. Endocrinol. 2001; 15: 2211-2228Crossref PubMed Scopus (139) Google Scholar). to the of RIAD on the type I signaling pathway and I PKA from mitochondria in cells with RIAD, which to inhibition of progesterone to the PKA phosphorylation in H. J. Biol. Chem. 1997; 272: Full Text Full Text PDF PubMed Scopus Google Scholar), of type I PKA anchoring by RIAD in steroid biosynthesis. This is to of the peptide as the estimated is in K. and C. of type I PKA anchoring by RIAD the progesterone synthesis and that steroidogenesis is on type I that RIAD is a of anchored PKA type I signaling in of type I PKA by RIAD, of PKA type anchored signaling can be in different cell and of type signaling and and to other signaling signaling PKA an in and RIAD also be used to with a PKA signaling is on anchored PKA type M. and for at the of at for with for to the of peptide array for the signaling and Langeberg and of the Scott and for