Immunocytochemical localization of phospholipase C-gamma in rat embryo fibroblasts.
Rat embryo fibroblasts (REF52) exhibit a distinctive, transformation-sensitive distribution of alpha-protein kinase C (alpha-PKC). Receptor-mediated activation of phospholipase C (PLC)-gamma generates diacylglycerol, the major cellular activator of PKC. Immunofluorescence techniques were used to investigate the subcellular localization of two PLC isozymes (PLC-gamma and PLC-delta) in normal and simian virus 40-transformed REF52 cells to determine (i) if PLC colocalizes with alpha-PKC and (ii) if PLC isozyme distribution is sensitive to transformation. PLC-delta was not detected in either cell type. In REF52 cells, PLC-gamma was associated with the actin cytoskeleton and was evenly distributed along the length of the actin microfilaments. PLC-gamma was coincident with alpha-PKC at the points where the filaments are anchored to the membrane (i.e., the focal contacts). Cytoskeletal association of PLC-gamma was not transformation sensitive, although the actin cytoskeleton was more disordered in simian virus 40-transformed cells. In REF52 cells, platelet-derived growth factor induced tyrosine phosphorylation of both soluble and cytoskeletal PLC-gamma. Tyrosine phosphorylation of PLC-gamma did not seem to be a determinant of its subcellular localization, but there was a detectable increase in cytoskeleton-associated PLC-gamma in response to platelet-derived growth factor treatment.
McBride
K
K
W Alton Jones Cell Science Center, Inc., Lake Placid, NY 12946.
Rhee
S G
SG
Jaken
S
S
D000818:Animals; D000911:Antibodies, Monoclonal; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D003598:Cytoskeletal Proteins / Q000032:analysis; D003599:Cytoskeleton / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure; D004622:Embryo, Mammalian; D005347:Fibroblasts / Q000201:enzymology; D005455:Fluorescent Antibody Technique; D007527:Isoenzymes / Q000032:analysis* / Q000378:metabolism; D008970:Molecular Weight; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D051381:Rats; D013539:Simian virus 40 / Q000235:genetics; D010738:Type C Phospholipases / Q000032:analysis* / Q000378:metabolism
D000911:Antibodies, Monoclonal; D003598:Cytoskeletal Proteins; D007527:Isoenzymes; D010982:Platelet-Derived Growth Factor; D010738:Type C Phospholipases