Identification of GTP-binding proteins in human glomeruli.
The localization of GTP-binding proteins (G-proteins) in human glomeruli was examined using immunohistochemistry and immunoblotting. Immunohistochemical staining for G-protein subunits demonstrated the existence of Gs alpha, Gi alpha and Go alpha proteins in the glomeruli. Moreover, immunoblots further revealed Gs alpha (52 kD), Gi alpha 1/2 (40-41 kD), Gi alpha 3 (40 kD) and Go alpha (39 kD) in the glomerular membranes. The predominant subspecies of Gs was a 52-kD protein, and Go alpha was detectable in the smallest amounts of the G-protein subunits. However, immunoblots failed to demonstrate detectable amounts of G-proteins in cytosolic extracts. This is the first report that characterizes G-protein subunits in human glomeruli. Further study is required to determine the roles of G-proteins in signal transductions in human glomeruli.
Nitta
K
K
Department of Medicine, Kidney Center, Tokyo Women's Medical College, Japan.
Uchida
K
K
Kawashima
A
A
Tsutsui
T
T
Ozu
H
H
Naito
T
T
Yumura
W
W
Nihei
H
H
D019204:GTP-Binding Proteins / Q000032:analysis*; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D007678:Kidney Glomerulus / Q000737:chemistry*; D010446:Peptide Fragments / Q000032:analysis
D010446:Peptide Fragments; D019204:GTP-Binding Proteins