Studies of the decrease of tyrosine-O-sulphated proteins in Rous sarcoma-virus-transformed rat embryo fibroblasts, line 3Y1. Examination of the sulphate activation and tyrosyl-protein sulphotransferase systems.
The sulphate activation and tyrosyl-protein sulphotransferase systems in normal 3Y1 rat embryo fibroblasts and the same cells transformed by Schmidt Ruppin subgroup-A-Rous sarcoma virus (SRA-3Y1) were examined. Employing metabolic [35S]sulphate-labelling followed by PEI (polyethyleneimine)-cellulose thin-layer chromatography of the labelled cell lysates, it was found that the steady-state level of 'active' sulphate, adenosine 3'-phosphate 5'-phosphosulphate, was drastically lower in SRA-3Y1 cells compared with their normal counterparts. When the sulphate activating enzymes were tested, it appeared that the activities in 3Y1 homogenates were 2-2.5 times greater than those in SRA-3Y1 homogenates. An endogenous sulphation assay for tyrosyl-protein sulphotransferase revealed that activities in 3Y1 and SRA-3Y1 homogenates were comparable. Nearly identical patterns were observed with both sets of cells when [35S]sulphated proteins generated in the endogenous assay were separated by two-dimensional gel electrophoresis. It therefore seems that the tyrosyl-protein sulphotransferase(s) are unimpaired in SRA-3Y1 cells. While the lower (approx. 8 times) sulphate uptake remains the major cause for the decrease of tyrosine-O-sulphated proteins in SRA-3Y1 cells [Liu & Lipmann, (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 3695-3698], the 2-2.5-fold lower sulphate activating enzyme activities also contribute to some extent to the difference between the SRA-3Y1 and 3Y1 cells.
Liu
M C
MC
Department of Chemistry, University of Oklahoma, Norman 73019.
Suiko
M
M
Lipmann
F
F
D000818:Animals; D001358:Avian Sarcoma Viruses; D002460:Cell Line; D002472:Cell Transformation, Viral; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000201:enzymology*; D010724:Phosphoadenosine Phosphosulfate / Q000378:metabolism; D051381:Rats; D013431:Sulfates / Q000378:metabolism*; D015238:Sulfotransferases; D013466:Sulfurtransferases / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism; D014764:Viral Proteins / Q000378:metabolism*
D013431:Sulfates; D014764:Viral Proteins; D014443:Tyrosine; D010724:Phosphoadenosine Phosphosulfate; D013466:Sulfurtransferases; D015238:Sulfotransferases; C039079:protein-tyrosine sulfotransferase