An anti-probasin monoclonal antibody recognizes a novel 40-kDa protein localized in rat liver and a specific region of kidney urinary tubule.
Immunoblotting with a monoclonal antibody against probasin (rat prostatic secretory protein) showed that a 40-kDa protein antigenically related to probasin was localized in rat liver and kidney. The contents of probasin in these organs were negligible. Immunostaining revealed that the 40-kDa protein (probasin-related antigen: PRB-RA) was expressed in the liver parenchymal cells and the kidney urinary tubular epithelial cells in outer stripe. The content of PRB-RA in the kidney was low during 0 to 2 weeks of age, then rapidly increased about 10-fold from 2 to 8 weeks of age. The content in the liver increased about 2-fold during the period, reaching a value of 10-12 ng/micrograms protein, which was ten times higher than that in the kidney. PRB-RA was purified from rat liver by ion-exchange chromatography, gel filtration and fast protein liquid chromatography on a hydroxyapatite column. The purified protein formed insoluble aggregates in the absence of a detergent, and it had a blocked amino terminal. The amino acid sequence of a peptide generated by tryptic digestion of alkylated PRB-RA was determined. Computer analysis showed that there was no protein having a significant homology with the peptide. These results indicate that a novel 40-kDa protein with a structural similarity to probasin is localized in rat liver and kidney, and might bear a function specific to these organs.
Nishi
N
N
Department of Endocrinology, Kagawa Medical School, Japan.
Kagawa
Y
Y
Miyanaka
H
H
Oya
H
H
Wada
F
F
D000375:Aging; D000478:Alkylation; D000727:Androgen-Binding Protein / Q000032:analysis* / Q000276:immunology / Q000302:isolation & purification; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D007124:Immunoenzyme Techniques; D007684:Kidney Tubules / Q000737:chemistry*; D008099:Liver / Q000737:chemistry*; D008297:Male; D010084:Oxidation-Reduction; D051381:Rats; D011919:Rats, Inbred Strains; D014357:Trypsin
D000727:Androgen-Binding Protein; D000911:Antibodies, Monoclonal; C027519:probasin; D014357:Trypsin