title: Identification and characterization of the murine TRPM4 channel.
abstract: The transient receptor potential (TRP) channels form a superfamily with six transmembrane structures, which is common in other types of voltage-dependent channels. The TRP-melastatin (TRPM) subfamily includes the putative tumor-suppressor melastatin, which was originally found as a down-regulated protein in melanoma tumor cell lines. Here, we report a novel TRP-related protein that is a murine orthologue of human TRPM4. The function of the novel murine TRPM4 was studied in HEK-293 cells using a fluorescent calcium indicator, fura-2. The removal and re-introduction of extracellular calcium triggered changes in the intracellular calcium only in cells expressing TRPM4a, which suggests that this novel channel plays a role in the calcium entry process. We also isolated a splice variant of TRPM4 that was proven to be non-functional. Both TRPM4 variants integrated into the plasma membrane. Furthermore, FRET analysis revealed that TRPM4a and TRPM4b localized close together, suggesting a multimerization of the two molecules.
authors.affiliation: Department of Pharmacology, Akita University School of Medicine, 1-1-1, Hondou, Akita 010-8543, Japan. manabumurakami@excite.co.jp
authors.forename: Manabu
authors.initials: M
authors.lastname: Murakami
authors.forename: Feng
authors.initials: F
authors.lastname: Xu
authors.forename: Ichiro
authors.initials: I
authors.lastname: Miyoshi
authors.forename: Eisaku
authors.initials: E
authors.lastname: Sato
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Ono
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Iijima
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000032:analysis / Q000235:genetics* / Q000378:metabolism*; D027682:Cation Transport Proteins; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry; D003001:Cloning, Molecular; D040461:Gene Components; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D050053:TRPM Cation Channels; D014018:Tissue Distribution; D014158:Transcription, Genetic
chemical_list: D015220:Calcium Channels; D027682:Cation Transport Proteins; D050053:TRPM Cation Channels; C476766:TRPM4 protein, mouse; D002118:Calcium