The role of novel 30-kD protein in human podocytes: special relevance to proteinuria in glomerulonephritis.
A new monoclonal antibody (MAb) was raised against human glomerular components to investigate the possible existence of glomerular antigens reflecting cellular adaptation in glomerulonephritis. The MAb recognized a podocyte antigen as well as those expressed on renal arterial endothelial cells and smooth muscle cells by indirect immunofluorescence. An additional, but weaker immunoreaction was found in epithelial cells of the Bowman's capsule. This MAb recognized a 30-kD protein on western blotting of glomerular extracts under non-reducing and reducing conditions. Immunoperoxidase electron microscopy revealed that this antigen is present within the cytoplasm, but not on the cell membrane of the podocytes. Moreover, the antigen was found to be reduced in the glomeruli of patients with minimal change glomerulonephritis. These results suggest that the 30-kD protein is a novel protein, which we hypothesize is involved in maintenance of the structural and functional integrity of the podocytes. In addition, reduced expression of the 30-kD protein in the podocytes may be related to the increasing proteinuria in minimal change glomerulonephritis.
Nitta
K
K
Department of Medicine, Tokyo Women's Medical College, Japan.
Uchida
K
K
Kawashima
A
A
Horita
S
S
Tsutsui
T
T
Ozu
H
H
Yumura
W
W
Nihei
H
H
D004848:Epithelium / Q000737:chemistry; D006801:Humans; D007678:Kidney Glomerulus / Q000737:chemistry* / Q000276:immunology; D009402:Nephrosis, Lipoid / Q000652:urine*; D011506:Proteins / Q000032:analysis / Q000502:physiology*; D011507:Proteinuria / Q000209:etiology*
D011506:Proteins