The 32P-labeled urokinase (uPA) bound to surface receptors of Detroit 562 cells was immunoprecipitated by anti-uPA antibody. Amino acid analysis showed that tyrosines and serines were the acceptors. Inhibition of protein kinases greatly reduced the 32P incorporation, suggesting that the respective cellular src gene product and protein kinase C were involved in the phosphorylations. Proteins purified on chromatographic columns contained two forms of uPA, a high (HMW) and a low (LMW) molecular weight. Tyrosine-phosphorylation occurs in the HMW and A-chain. Such modifications might modulate the extracellular activities of uPA.
|Original language||English (US)|
|Number of pages||7|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Feb 14 1992|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology