title: Expression of TRPC4 channel protein that interacts with NHERF-2 in rat descending vasa recta.
abstract: The PDZ domain adaptor protein Na+/H+ exchanger regulatory factor (NHERF)-2 is expressed in renal medullary descending vasa recta (DVR), although its function has not been defined. Transient receptor potential channels (TRPC) TRPC4 and TRPC5, nonselective cation channels that transport Ca2+, were recently demonstrated to complex with the NHERF proteins. We investigated whether TRPC4 and/or TRPC5 are associated with NHERF-2 in DVR. RT-PCR revealed mRNA for TRPC4 and NHERF-2, but not for TRPC5 or NHERF-1, in microdissected DVR. Immunohistochemical studies demonstrated expression of TRPC4 and NHERF-2 proteins in both the endothelial cells and pericytes. These proteins colocalized in some cells of the DVR. TRPC4 coimmunoprecipitated with NHERF-2 from renal medullary lysates, and NHERF-2 coimmunoprecipitated with TRPC4. TRPC5 was not detected in DVR with the use of immunohistochemistry or in NHERF-2 immunoprecipitates. We conclude that DVR pericytes and endothelia coexpress TRPC4 and NHERF-2 mRNA and protein and that these proteins colocalize and coimmunoprecipitate, indicating a possible physical association. These findings suggest that TRPC4 and NHERF-2 may play a role in interactions related to Ca2+ signaling.
authors.affiliation: Division of Nephrology, Department of Medicine, Univ. Maryland School of Medicine, N3W143, UMH, 22 S. Greene St., Baltimore, MD 21201, USA.
authors.forename: Whaseon
authors.initials: W
authors.lastname: Lee-Kwon
authors.forename: James B
authors.initials: JB
authors.lastname: Wade
authors.forename: Zhong
authors.initials: Z
authors.lastname: Zhang
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Pallone
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Weinman
mesh_terms: D000818:Animals; D015153:Blotting, Western; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism*; D005260:Female; D007150:Immunohistochemistry; D007473:Ion Channels / Q000378:metabolism*; D007668:Kidney / Q000098:blood supply*; D008833:Microcirculation; D018613:Microscopy, Confocal; D020286:Pericytes / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050052:TRPC Cation Channels
chemical_list: D003598:Cytoskeletal Proteins; D007473:Ion Channels; D012333:RNA, Messenger; D050052:TRPC Cation Channels; C489571:TRPC4 ion channel