Elevated membrane association of phospholipase C-gamma 1 in MDA-468 mammary tumor cells.

Abstract

We have examined the distribution of phospholipase C-gamma 1 (PLC-gamma 1) between membrane and cytosolic fractions in several cell lines. In MDA-468 cells, which are derived from a human breast tumor, greater than one-half of the total PLC-gamma 1 is associated with the membrane fraction of the cell. Unlike the situation in A-431 cells [G. Todderud, M. I. Wahl, S. G. Ree, and G. Carpenter, Science, 248: 296-298, 1990], epidermal growth factor (EGF) stimulation of MDA-468 cells does not result in significantly increased PLC-gamma 1 association with membranes. Immunoblot analysis reveals low levels of phosphotyrosine in PLC-gamma 1 and EGF receptors in unstimulated MDA-468 cells and greatly increased phosphotyrosine levels in these proteins as a result of EGF stimulation of the cells. We conclude that autocrine activation of EGF receptors is not responsible for the elevated association of PLC-gamma 1 with membranes in these cells.

• Authors: A M Soderquist, G Todderud, G Carpenter
• Journal: Cancer research (Cancer Res) Vol. 52 Issue 16 Pg. 4526-9 (Aug 15 1992) ISSN: 0008-5472 [Print] United States
• PMID: 1643644 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Isoenzymes
• Epidermal Growth Factor
• ErbB Receptors
• Protein-Tyrosine Kinases
• Type C Phospholipases

Topics

• Animals
• Cell Membrane (chemistry)
• Cytosol (chemistry)
• Electrophoresis, Polyacrylamide Gel
• Epidermal Growth Factor (pharmacology)
• ErbB Receptors (analysis, metabolism)
• Isoenzymes (analysis, metabolism)
• Mammary Neoplasms, Experimental (chemistry, metabolism)
• Phosphorylation
• Protein-Tyrosine Kinases (metabolism)
• Tumor Cells, Cultured
• Type C Phospholipases (analysis, metabolism)