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Retrovirus transformation associated secretory phosphoproteins of mouse and mink cells
1Department of Anatomy and Cell Biology, State University of New York, Brooklyn 11203.
Abstract:
Using antisera to major excreted protein (MEP) of Kirsten sarcoma virus transformed NIH 3T3 (KNIH) cells, we have identified phosphoproteins from the media of feline sarcoma virus (FeSV) transformed mink cells. These secretory phosphoproteins from FeSV-transformed mink cells are of 35 kDa M.W. and they do not have autophosphorylation activity. A comparative analysis of MEP from the media of transformed mouse and mink cells was performed on the basis of proteolytic cleavage products and acid hydrolyzed products of the phosphoproteins. While a marked difference was observed in the peptide map, a common 32P-linked molecule was observed following acid hydrolysis of both species of phosphoproteins.
Insights
Researchers identified secretory phosphoproteins in feline sarcoma virus (FeSV) transformed mink cells. These proteins, related to major excreted protein (MEP), show distinct peptide maps but share a common phosphorylated molecule.
Area of Science:
- Virology
- Cell Biology
- Biochemistry
Background:
- Kirsten sarcoma virus (K-RASV) and feline sarcoma virus (FeSV) are retroviruses known to transform cells.
- Major excreted protein (MEP) is a protein found in the media of transformed cells.
- Identifying secreted proteins from transformed cells can provide insights into viral oncogenesis.
Purpose of the Study:
- To identify and characterize secretory phosphoproteins in feline sarcoma virus (FeSV) transformed mink cells.
- To compare these phosphoproteins with those from Kirsten sarcoma virus (K-RASV) transformed mouse cells.
- To investigate the structural similarities and differences between MEP from different transformed cell types.
Main Methods:
- Utilized antisera against major excreted protein (MEP) for immunoprecipitation.
- Analyzed secreted phosphoproteins from FeSV-transformed mink cell media.
- Performed comparative analysis using proteolytic cleavage and acid hydrolysis.
- Examined peptide maps and 32P-linked molecules.
Main Results:
- Identified 35 kDa secretory phosphoproteins in FeSV-transformed mink cells.
- These phosphoproteins lack autophosphorylation activity.
- Peptide mapping revealed significant differences between MEP from transformed mouse and mink cells.
- A common 32P-linked molecule was found after acid hydrolysis of both phosphoprotein types.
Conclusions:
- FeSV-transformed mink cells secrete 35 kDa phosphoproteins related to MEP.
- Despite differences in peptide structure, a conserved phosphorylated component exists in MEP from different species.
- These findings contribute to understanding the molecular mechanisms of viral transformation and protein secretion.