Interaction of membrane skeletal protein, protein 4.1B and p55, and sodium bicarbonate cotransporter1 in mouse renal S1-S2 proximal tubules.
Our recent studies demonstrated the localization of protein 4.1B, a member of the 4.1 skeletal membrane proteins, to the basolateral membranes of the S1-S2 renal proximal tubules. In the present studies, we investigated the presence of binding partners that could form a molecular complex with the 4.1B protein. Immunohistochemistry revealed the localization of p55, a membrane-associated guanylate kinase, and the sodium bicarbonate cotransporter1 (NBC1), to the basolateral membrane domain of S1-S2 in mouse renal proximal tubules. Using immunoprecipitation of kidney lysates with anti-p55 antibody, a positive band was blotted with anti-4.1B antibody. GST fusion proteins including the NBC1 and 4.1B regions were confirmed to bind with each other by electrophoresis after mixing. Both NBC1- and 4.1B-specific bands were detected in renal protein mixtures immunoprecipated by either anti-4.1B- or NBC1-specific antibodies. It is likely that NBC1, 4.1B, and p55 form a molecular complex in the basolateral membrane of the kidney S1-S2 proximal tubules. We propose that the 4.1B-containing membrane skeleton may play a role in regulating the Na(+) and HCO(3)(-) reabsorption in S1-S2 proximal tubules.
Terada
Nobuo
N
Department of Anatomy and Molecular Histology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokato, Chuo City, Yamanashi 409-3898, Japan. nobuot@yamanashi.ac.jp
Ohno
Nobuhiko
N
Saitoh
Sei
S
Seki
George
G
Komada
Masayuki
M
Suzuki
Tatsuo
T
Yamakawa
Hisashi
H
Soleimani
Manoocher
M
Ohno
Shinichi
S
D000818:Animals; D000831:Animals, Newborn; D051528:Guanylate Kinases / Q000378:metabolism*; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D007687:Kidney Tubules, Proximal / Q000254:growth & development / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008840:Microfilament Proteins; D016253:Microscopy, Immunoelectron; D027982:Sodium-Bicarbonate Symporters / Q000378:metabolism*
C488402:Epb41l3 protein, mouse; D008565:Membrane Proteins; D008840:Microfilament Proteins; D027982:Sodium-Bicarbonate Symporters; D051528:Guanylate Kinases