Expression and Characterization of Human Transient Receptor Potential Melastatin 3 (hTRPM3)

Abstract

Transient receptor potential (TRP) cation-selective channels are an emerging class of proteins that are involved in a variety of important biological functions including pain transduction, thermosensation, mechanoregulation, and vasorelaxation. Utilizing a bioinformatics approach, we have identified the full-length human TRPM3 (hTRPM3) as a member of the TRP family. The hTRPM3 gene is comprised of 24 exons and maps to human chromosome 9q-21.12. hTRPM3 is composed of 1555 amino acids and possesses the characteristic six-transmembrane domain of the TRP family. hTRPM3 is expressed primarily in kidney and, at lesser levels, in brain, testis, and spinal cord as demonstrated by quantitative RT-PCR and Northern blotting. In situ hybridization in human kidney demonstrated that hTRPM3 mRNA expression is predominantly found in the collecting tubular epithelium. Heterologous expression of hTRPM3 in human embryonic kidney cells (HEK 293) showed that hTRPM3 is localized to the cell membrane. hTRPM3-expressing cells exhibited Ca2+ concentration-dependent Ca2+ entry. Depletion of intracellular Ca2+ stores by lowering extracellular Ca2+ concentration and treatment with the Ca2+-ATPase inhibitor thapsigargin or the muscarinic receptor agonist carbachol further augmented hTRPM3-mediated Ca2+ entry. The nonselective Ca2+ channel blocker, lanthanide gadolinium (Gd3+), partially inhibited hTRPM3-mediated Ca2+ entry. These results are consistent with the hypothesis that hTRPM3 mediates a Ca2+ entry pathway that apparently is distinct from the endogenous Ca2+ entry pathways present in HEK 293 cells. Transient receptor potential (TRP) cation-selective channels are an emerging class of proteins that are involved in a variety of important biological functions including pain transduction, thermosensation, mechanoregulation, and vasorelaxation. Utilizing a bioinformatics approach, we have identified the full-length human TRPM3 (hTRPM3) as a member of the TRP family. The hTRPM3 gene is comprised of 24 exons and maps to human chromosome 9q-21.12. hTRPM3 is composed of 1555 amino acids and possesses the characteristic six-transmembrane domain of the TRP family. hTRPM3 is expressed primarily in kidney and, at lesser levels, in brain, testis, and spinal cord as demonstrated by quantitative RT-PCR and Northern blotting. In situ hybridization in human kidney demonstrated that hTRPM3 mRNA expression is predominantly found in the collecting tubular epithelium. Heterologous expression of hTRPM3 in human embryonic kidney cells (HEK 293) showed that hTRPM3 is localized to the cell membrane. hTRPM3-expressing cells exhibited Ca2+ concentration-dependent Ca2+ entry. Depletion of intracellular Ca2+ stores by lowering extracellular Ca2+ concentration and treatment with the Ca2+-ATPase inhibitor thapsigargin or the muscarinic receptor agonist carbachol further augmented hTRPM3-mediated Ca2+ entry. The nonselective Ca2+ channel blocker, lanthanide gadolinium (Gd3+), partially inhibited hTRPM3-mediated Ca2+ entry. These results are consistent with the hypothesis that hTRPM3 mediates a Ca2+ entry pathway that apparently is distinct from the endogenous Ca2+ entry pathways present in HEK 293 cells. Intracellular Ca2+ plays a pivotal role in various cellular functions such as protein secretion, cell differentiation, cell division, and apoptosis. Ca2+ entry into cells can be mediated via voltage-dependent Ca2+ channels, ligand-gated Ca2+ channels, nonselective cation channels, and the relatively less characterized class store-operated Ca2+ channels (SOC). 1The abbreviations used are: SOC, store-operated Ca2+ channel; TRP, transient receptor potential; HEK, human embryonic kidney; TG, thapsigargin; HMM, hidden Markov model; FLIPR, fluorometric imaging plate reader; CCh, carbachol; hemagglutinin; RT, reverse transcriptase; Gd3+, lanthanide gadolinium; HSH, hypomagnesemia with secondary hypocalcemia. SOC mediate Ca2+ entry from the extracellular space following Ca2+ release from the intracellular stores to generate sustained increases in intracellular Ca2+ concentration and replenish the internal Ca2+ stores. The molecular mechanism of SOC activation and the molecular identity of SOC remain elusive. Transient receptor potential (TRP) channels, an emerging class of the Ca2+-permeable cation channel superfamily, are probable candidates for SOC (for review see Ref. 1Harteneck C. Plant T D. Schultz G. Trends Neurosci. 2000; 23: 159-166Abstract Full Text Full Text PDF PubMed Scopus (434) Google Scholar). Following the identification of the founding member of this family, dTRP, which is from a Drosophila mutant with abnormal visual signal transduction (2Hardie R.C. Minke B. Neuron. 1992; 8: 643-651Abstract Full Text PDF PubMed Scopus (595) Google Scholar), mammalian homologues have been cloned and all of them contain a six-transmembrane domain followed by a TRP motif (XWKFXR). Based on homology, they are divided into three subfamilies: TRPC (canonical), TRPV (vanilloid), and TRPM (melastatin) (3Montell C Birnbaumer L. Flockerzi V. Bindels R.J. Bruford E.A. Caterina M.J. Clapham D.E. Harteneck C. Heller S. Julius D. Kojima I. Mori Y. Penner R. Prawitt D. Scharenberg A.M. Schultz G. Shimizu N. Zhu M.X. Mol. Cell. 2002; 9: 229-231Abstract Full Text Full Text PDF PubMed Scopus (580) Google Scholar). Members of the TRPM subfamily have unusually long cytoplasmic tails at both ends of the channel domain, and some of the family members have an enzyme domain in the C-terminal region. Despite their similarities of structure, TRPMs have different ion-conductive properties, activation mechanisms, and putative biological functions. TRPM1 is down-regulated in metastatic melanomas (4Duncan L.M. Deeds J. Hunter J. Shao J. Holmgren L.M. Woolf E.A. Tepper R.I. Shyjan A.W. Cancer Res. 1998; 58: 1515-1520PubMed Google Scholar). TRPM2 is a Ca2+-permeable channel that contains an ADP-ribose pyrophosphatase domain and can be activated by ADP-ribose, NAD (5Perraud A.L. Fleig A. Dunn C.A. Bagley L.A. Launay P. Schmitz C. Stokes A.J. Zhu Q. Bessman M.J. Penner R. Kinet J.P. Scharenberg A.M. Nature. 2001; 411: 595-599Crossref PubMed Scopus (772) Google Scholar, 6Sano Y. Inamura K. Miyake A. Mochizuki S. Yokoi H. Matsushime H. Furuichi K. Science. 2001; 293: 1327-1330Crossref PubMed Scopus (393) Google Scholar), and changes in redox status (7Hara Y. Wakamori M. Ishii M. Maeno E. Nishida M. Yoshida T. Yamada H. Shimizu S. Mori E. Kudoh J. Shimizu N. Kurose H. Okada Y. Imoto K. Mori Y. Mol. Cell. 2002; 9: 163-173Abstract Full Text Full Text PDF PubMed Scopus (708) Google Scholar). The TRPM2 gene is mapped to the chromosome region linked to bipolar affective disorder, nonsyndromic hereditary deafness, Knobloch syndrome, and holosencephaly (8Nagamine K. Kudoh J. Minoshima S. Kawasaki K. Asakawa S. Ito F. Shimizu N. Genomics. 1998; 54: 124-131Crossref PubMed Scopus (216) Google Scholar). Two splice variants of TRPM4 have been described. TRPM4a is predominantly a Ca2+-permeable channel (9Xu X.-Z.S. Moebius F. Gill D.L. Montell C. Proc. Natl. Acad. Sci. U. S. A. 2001; 98: 10692-10697Crossref PubMed Scopus (191) Google Scholar); whereas TRPM4b conducts monovalent cations upon activation by changes in intracellular Ca2+ (10Launay P. Fleig A. Perraud A.-L. Scharenberg A.M. Penner R. Kinet J.-P. Cell. 2002; 109: 397-407Abstract Full Text Full Text PDF PubMed Scopus (568) Google Scholar). TRPM5 is associated with Beckwith-Wiedemann syndrome and a predisposition to neoplasias (11Prawitt D. Enklaar T. Klemm G. Gartner B. Spangenberg C. Winterpacht A. Higgins M. Pelletier J. Zabel B. Hum. Mol. Genet. 2000; 9: 203-216Crossref PubMed Scopus (114) Google Scholar). TRPM7, another bifunctional protein, has kinase activity in addition to its ion channel activity. TRPM7 is regulated by Mg2+-ATP and/or inositol 1,4,5-disphosphate and is required for cell viability (12Runnels L.W. Yue L. Clapham D.E. Science. 2001; 291: 1043-1047Crossref PubMed Scopus (648) Google Scholar, 13Nadler M.J. Hermosura M.C. Inabe K. Perraud A.L. Zhu Q. Stokes A.J. Kurosaki T. Kinet J.P. Penner R. Scharenberg A.M. Fleig A. Nature. 2001; 411: 590-595Crossref PubMed Scopus (825) Google Scholar, 14Runnels L.W. Yue L. Clapham D.E. Nat. Cell Biol. 2002; 4: 329-336Crossref PubMed Scopus (466) Google Scholar). TRPM8 is up-regulated in prostate cancer and other malignancies (15Tsavaler L. Shapero M.H. Morkowski S. Laus R. Cancer Res. 2001; 61: 3760-3769PubMed Google Scholar). Recently, it has been shown to be a receptor that senses cold stimuli (16McKemy D.D. Neuhausser W.M. Julius D. Nature. 2002; 416: 52-58Crossref PubMed Scopus (2066) Google Scholar, 17Peier A.M. Moqrich A. Hergarden A.C. Reeve A.J. Andersson D.A. Story G.M. Earley T.J. Dragoni I. McIntyre P. Bevan S. Patapoutian A. Cell. 2002; 108: 705-715Abstract Full Text Full Text PDF PubMed Scopus (1810) Google Scholar). Using a bioinformatics approach, we have identified a member of the human TRPM subfamily that we have called hTRPM3, consistent with the unified TRP nomenclature (3Montell C Birnbaumer L. Flockerzi V. Bindels R.J. Bruford E.A. Caterina M.J. Clapham D.E. Harteneck C. Heller S. Julius D. Kojima I. Mori Y. Penner R. Prawitt D. Scharenberg A.M. Schultz G. Shimizu N. Zhu M.X. Mol. Cell. 2002; 9: 229-231Abstract Full Text Full Text PDF PubMed Scopus (580) Google Scholar). hTRPM3 contains long N and C termini, although it does not contain any additional enzymatic features. hTRPM3 mRNA is expressed primarily in kidney with lower levels in brain, testis, and spinal cord. When expressed in HEK 293 cells, hTRPM3 is co-localized with the plasma membrane and is capable of mediating Ca2+ entry. This hTRPM3-mediated Ca2+ conductance is partially lanthanide gadolinium (Gd3+)-sensitive and can be enhanced upon Ca2+ stores depletion or receptor activation. Bioinformatics Analysis—The sequence homology search program BLAST and the gene-finding program Genewise/Wise2 package (18Altschul S.F. Madden T.L. Schaffer A.A. Zhang J. Zhang Z. Miller W. Lipman D.J. Nucleic Acids Res. 1997; 25: 3389-3402Crossref PubMed Scopus (61086) Google Scholar, 19Bateman A. Berney E. Durbin R. Eddy S.R. Howe K.L. Sonnhammer E.L. Nucleic Acids Res. 2000; 28: 263-266Crossref PubMed Scopus (1237) Google Scholar) were used to identify novel ion channel sequences in the TRP family. Individual known ion channel protein sequences in the TRP family were used as probes in a TBLASTN analysis versus the human genome sequence. A multiple sequence alignment of known TRP family members was also the alignment program in the A hidden Markov for the TRP family was the program in package from the multiple sequence alignment S.R. 1998; PubMed Scopus Google Scholar). This was used to search the human sequence the program in from the TBLASTN and were The from the search were and protein and sequence to potential novel the protein sequence were used as to putative exons from the sequence the this exons potential novel ion channels were the and sequences of putative novel ion channel the the exons from were and to generate exons C. S. J. Mol. Biol. 1997; PubMed Scopus Google Scholar, A.A. Res. 2000; PubMed Scopus Google Scholar). Based on of the full-length protein sequences of novel human ion channel was cloned for further The for the TRPM subfamily was by the the program with Members of TRP family with their are as and of the sequence from were and and and used to from the human kidney The in contains of and of The was for for for and for The were cloned into the for sequence The were to generate the full-length the was with an at its C and into the mammalian expression was to the levels of TRPM3 mRNA by quantitative a of the were in The was from mRNA from The of used in was by a a from These were used for of the with the for the hTRPM3 The were into a of the in the Northern Northern were with an from a from the of the was at in for with was for at In was and from the to were in and by in in and at The were by a to the of the the following for hTRPM3 probes were from a hTRPM3 cloned in a the The for human was from a expression sequence were via in the and and for hTRPM3, whereas and and for human at and in were used for in situ hybridization as L.M. D.L. 2002; PubMed Scopus Google Scholar). were in a in and with and probes for at Following were in and with A at to a in at and with were in a with at and a and were with and and were by identification was by The results have been in the kidney from three different and from Cell and of 293 cells were in and on The cells were with with cells were in with the membrane at for and for with cells were with in with in and and with and cell were a a and shown are of a of in Intracellular cytoplasmic Ca2+ and a fluorometric imaging plate were used to changes in intracellular Ca2+ The cells were on at a of 24 and used 24 were with at for in a or and was and cells were in or Ca2+ at to the which were was at an and was a intracellular was the of the and or Ca2+ was to and changes in the intracellular Ca2+ were for or receptor activation thapsigargin or carbachol was to cells in Ca2+ on was to cells in or Ca2+ as in to the of the were at hTRPM3 a of the TRP was found to a of a novel TRP family gene on the and the protein for this novel TRP was used as a to additional exons from the sequence the the and sequences of the TRP the the exons in sequence were and to generate exons C. S. J. Mol. Biol. 1997; PubMed Scopus Google Scholar, A.A. Res. 2000; PubMed Scopus Google Scholar). A full-length TRP family gene was This was A was from a human kidney by the putative sequences as to this gene as hTRPM3 (3Montell C Birnbaumer L. Flockerzi V. Bindels R.J. Bruford E.A. Caterina M.J. Clapham D.E. Harteneck C. Heller S. Julius D. Kojima I. Mori Y. Penner R. Prawitt D. Scharenberg A.M. Schultz G. Shimizu N. Zhu M.X. Mol. Cell. 2002; 9: 229-231Abstract Full Text Full Text PDF PubMed Scopus (580) Google Scholar). The C-terminal sequence is to a T. R. M. M. Res. 2000; Google Scholar) and as TRPM3 (3Montell C Birnbaumer L. Flockerzi V. Bindels R.J. Bruford E.A. Caterina M.J. Clapham D.E. Harteneck C. Heller S. Julius D. Kojima I. Mori Y. Penner R. Prawitt D. Scharenberg A.M. Schultz G. Shimizu N. Zhu M.X. Mol. Cell. 2002; 9: 229-231Abstract Full Text Full Text PDF PubMed Scopus (580) Google Scholar). with sequence contains additional amino acids at the N of the following we that we have the full-length hTRPM3 is to be 1555 amino acids long and is comprised of the following characteristic of a TRP an ion domain acids a TRP motif of the and a domain further of the TRP domain some of the TRPM family members including TRPM2 (5Perraud A.L. Fleig A. Dunn C.A. Bagley L.A. Launay P. Schmitz C. Stokes A.J. Zhu Q. Bessman M.J. Penner R. Kinet J.P. Scharenberg A.M. Nature. 2001; 411: 595-599Crossref PubMed Scopus (772) Google Scholar, 6Sano Y. Inamura K. Miyake A. Mochizuki S. Yokoi H. Matsushime H. Furuichi K. Science. 2001; 293: 1327-1330Crossref PubMed Scopus (393) Google Scholar), TRPM7 (12Runnels L.W. Yue L. Clapham D.E. Science. 2001; 291: 1043-1047Crossref PubMed Scopus (648) Google Scholar, 13Nadler M.J. Hermosura M.C. Inabe K. Perraud A.L. Zhu Q. Stokes A.J. Kurosaki T. Kinet J.P. Penner R. Scharenberg A.M. Fleig A. Nature. 2001; 411: 590-595Crossref PubMed Scopus (825) Google Scholar, 14Runnels L.W. Yue L. Clapham D.E. Nat. Cell Biol. 2002; 4: 329-336Crossref PubMed Scopus (466) Google Scholar), and hTRPM3 does not contain an enzyme domain in the C-terminal cytoplasmic region. hTRPM3 is to with identity and A and homology was at the N amino acids and is a amino in the hTRPM3 sequences as shown in the alignment of hTRPM3 with was used to for exons at the and was are splice the sequence and the by has homology to it is that any sequence was that region. hTRPM3 at analysis of the sequence of hTRPM3 showed that the region and is comprised of 24 hTRPM3 gene is the and and its is 9q-21.12. identified splice variants from a human kidney the from the sequence of hTRPM3 gene A with the sequence that the of all of the splice variants the of the splice the splice variants as to their to the of from the The following were all the hTRPM3 in the expression of hTRPM3 various human mRNA by Northern analysis a to the region The of to hTRPM3 are expressed in kidney The hTRPM3 was also expressed at lesser levels in the and with the identification of other splice multiple of hTRPM3 were also in the Northern A expression was by an quantitative shown in to hTRPM3 expressed in kidney and, at lesser levels, in brain, testis, and spinal cord. an of human it was demonstrated that the levels of expression were found in the the the and the not hTRPM3 mRNA expression in human kidney was further by in situ hTRPM3 was localized to the of collecting tubular in the and and in the exhibited the tubular tubular exhibited were with human kidney as and and to human human kidney as not analysis of hTRPM3 expression has also been in mRNA from various and showed a of in hTRPM3 mRNA levels in the with their kidney in lower mRNA levels also were not These that a of hTRPM3 expression a role in hTRPM3 at the in HEK 293 of hTRPM3 with a C-terminal was into HEK 293 cells to the biological The expression of full-length protein was with the an and as the of not The cellular of hTRPM3 was a and a was found to be associated with the membrane hTRPM3 protein in or the of cells is consistent with the of the TRP family as Ca2+-permeable membrane hTRPM3 was also in intracellular from in this expression as with other ion channels J. R. Howe Neuron. Full Text PDF PubMed Scopus Google Scholar). hTRPM3 the role of hTRPM3, we for Ca2+ a to TRP with or hTRPM3 were with the cytoplasmic Ca2+ Intracellular Ca2+ was a that intracellular cells were in a Ca2+ which is in the of intracellular Ca2+ upon addition of or to the in a concentration-dependent in intracellular Ca2+ in hTRPM3-expressing cells In cells showed Ca2+ entry the cells were from cells not These results that hTRPM3 is capable of mediating Ca2+ entry. further the mechanism of hTRPM3-mediated Ca2+ Ca2+ addition were on cells in a have shown that lowering extracellular Ca2+ concentration levels can intracellular Ca2+ stores in cell including HEK 293 S. J. L. G. M. M. A. Flockerzi V. J. 1998; PubMed Scopus Google Scholar). HEK 293 cells in a to Ca2+ entry that was on the concentration of Ca2+ to the that Ca2+ entry was mediated endogenous in HEK 293 cells In cells, the Ca2+ by a Ca2+ treatment were In Ca2+ entry in cells in was in Ca2+ with that hTRPM3-mediated Ca2+ entry was by The store-operated mechanism of hTRPM3-mediated Ca2+ entry was further by Ca2+ stores with TG, an inhibitor of Ca2+-ATPase is to from the into the stores. The addition of Ca2+ stores in and cells Following depletion with TG, the addition of Ca2+ to the a Ca2+ entry in hTRPM3 cells with the cells at from hTRPM3, Ca2+ entry was also in cells. can an endogenous muscarinic receptor and inositol to the activation of in HEK 293 cells M. Birnbaumer L. J. Biol. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar). The addition of a transient and intracellular Ca2+ in both and cells the receptor activation with CCh, the addition of Ca2+ to the a of Ca2+ into hTRPM3 cells as with cells at from hTRPM3, These results that depletion with or receptor activation with CCh, cells an Ca2+ with cells. hTRPM3-mediated by is a nonselective Ca2+-permeable channel that known TRP The of on Ca2+ were in and cells. The Ca2+ upon the addition of Ca2+ to the cells were in the of in cells was inhibited by In inhibited Ca2+ entry by Ca2+ by in cells in cells from to and in cells from to were and was as in the of The of on hTRPM3-mediated Ca2+ entry by Ca2+ in the of or were also were in for and inhibited Ca2+ entry by depletion of intracellular stores with Ca2+ addition in cells from to and in cells from to C and inhibited Ca2+ entry by depletion of intracellular stores with Ca2+ in cells from to and in cells from to and These results that the endogenous Ca2+ entry pathway was by the of Gd3+, whereas the mediated pathway was partially A and of Ca2+ entry in cells in the of or was also partially by These results are consistent with the hypothesis that hTRPM3 mediates a Ca2+ entry pathway that apparently is distinct from the endogenous Ca2+ entry pathways present in HEK 293 cells. have identified the full-length hTRPM3 as a member of the TRP channel family. hTRPM3 is predominantly expressed in human kidney and, at lesser levels, in brain, testis, and spinal cord. In the hTRPM3 is localized in the collecting tubular as demonstrated by in situ have also shown that expressed in HEK 293 cells, hTRPM3 is capable of mediating Ca2+ entry and is partially inhibited by hTRPM3-mediated Ca2+ entry is distinct from Ca2+ entry in cells, which is by Ca2+ entry via hTRPM3 was enhanced depletion of Ca2+ stores with or hTRPM3 is the member of the TRPM subfamily that has been shown to be by is of to that some members of the TRPC and TRPV also are by depletion (for review see Ref. 1Harteneck C. Plant T D. Schultz G. Trends Neurosci. 2000; 23: 159-166Abstract Full Text Full Text PDF PubMed Scopus (434) Google Scholar). The known TRPM subfamily members channel TRPM1 and TRPM4a are Ca2+-permeable channels, it is they can be by depletion (9Xu X.-Z.S. Moebius F. Gill D.L. Montell C. Proc. Natl. Acad. Sci. U. S. A. 2001; 98: 10692-10697Crossref PubMed Scopus (191) Google Scholar). from TRPM4b is activated by changes in intracellular Ca2+ of Ca2+ (10Launay P. Fleig A. Perraud A.-L. Scharenberg A.M. Penner R. Kinet J.-P. Cell. 2002; 109: 397-407Abstract Full Text Full Text PDF PubMed Scopus (568) Google Scholar). TRPM2 is activated by ADP-ribose, and changes in redox status (5Perraud A.L. Fleig A. Dunn C.A. Bagley L.A. Launay P. Schmitz C. Stokes A.J. Zhu Q. Bessman M.J. Penner R. Kinet J.P. Scharenberg A.M. Nature. 2001; 411: 595-599Crossref PubMed Scopus (772) Google Scholar, 6Sano Y. Inamura K. Miyake A. Mochizuki S. Yokoi H. Matsushime H. Furuichi K. Science. 2001; 293: 1327-1330Crossref PubMed Scopus (393) Google Scholar, Y. Wakamori M. Ishii M. Maeno E. Nishida M. Yoshida T. Yamada H. Shimizu S. Mori E. Kudoh J. Shimizu N. Kurose H. Okada Y. Imoto K. Mori Y. Mol. Cell. 2002; 9: 163-173Abstract Full Text Full Text PDF PubMed Scopus (708) Google Scholar). TRPM7 is regulated by Mg2+-ATP and/or inositol 1,4,5-disphosphate (12Runnels L.W. Yue L. Clapham D.E. Science. 2001; 291: 1043-1047Crossref PubMed Scopus (648) Google Scholar, 13Nadler M.J. Hermosura M.C. Inabe K. Perraud A.L. Zhu Q. Stokes A.J. Kurosaki T. Kinet J.P. Penner R. Scharenberg A.M. Fleig A. Nature. 2001; 411: 590-595Crossref PubMed Scopus (825) Google Scholar, 14Runnels L.W. Yue L. Clapham D.E. Nat. Cell Biol. 2002; 4: 329-336Crossref PubMed Scopus (466) Google Scholar). TRPM8 is activated by cold and (16McKemy D.D. Neuhausser W.M. Julius D. Nature. 2002; 416: 52-58Crossref PubMed Scopus (2066) Google Scholar, 17Peier A.M. Moqrich A. Hergarden A.C. Reeve A.J. Andersson D.A. Story G.M. Earley T.J. Dragoni I. McIntyre P. Bevan S. Patapoutian A. Cell. 2002; 108: 705-715Abstract Full Text Full Text PDF PubMed Scopus (1810) Google Scholar). in with a expression not with any other family hTRPM3 have a biological in have shown that hTRPM3-mediated Ca2+ entry can be by lowering extracellular Ca2+ concentration by Ca2+ stores with treatment and by treatment with that The Ca2+ entry was by Ca2+ to the in hTRPM3-expressing cells whereas the addition of Ca2+ to the hTRPM3 activity in cells of which intracellular Ca2+ stores were not with These results that Ca2+ entry in cells was by some TRPC subfamily members such as and which activation of the depletion (for review see Ref. 1Harteneck C. Plant T D. Schultz G. Trends Neurosci. 2000; 23: 159-166Abstract Full Text Full Text PDF PubMed Scopus (434) Google Scholar). The hTRPM3 gene maps to chromosome the and that have been linked to this region with and hypomagnesemia with secondary its expression in hTRPM3 be a gene for HSH, the is a The of hTRPM3 is of an for with H. R. K. D.A. A. A.L. S. Hum. Mol. Genet. 1997; PubMed Scopus Google Scholar). Recently, S. M. L. H. K. M. E. E. D. M. S. M. S. M. Nat. Genet. 2002; PubMed Scopus Google Scholar, D. P. H. M. Z. R. Nat. Genet. 2002; PubMed Scopus Google Scholar) that a member of the TRPM expressed in both and is associated with human TRPM3 is to on has been in HSH, this not the of The kidney plays a role in Ca2+ hTRPM3 be involved in Ca2+ of its Ca2+ the in situ hybridization analysis demonstrated that hTRPM3 is predominantly present in the collecting which has been in Ca2+ (for review see Ref. B. Bindels R.J. 2002; PubMed Scopus Google Scholar). hTRPM3 as a SOC that Ca2+ In the Ca2+ is regulated by such as and their and (for review see Ref. PubMed Scopus Google Scholar). or the role of hTRPM3 in the and for and for with quantitative RT-PCR for with and for and