Polyoma virus middle tumor antigen stimulates membrane-associated protein kinase C at lower levels than required for phosphatidylinositol kinase activation and neoplastic transformation.
Twelve independent rat F111 cell lines expressing the polyoma virus middle tumor antigen (mT) under control of the dexamethasone-regulatable MMTV-LTR promoter were assayed for levels of membrane-associated protein kinase C (PKC) activity. Low background levels of mT antigen expression (approximately 2%), although insufficient for transformation, triggered a dramatic increase in PKC activity. Under the same conditions, levels of the mT-associated phosphatidylinositol kinase activity were low, indicating that this kinase might be a factor limiting transformation in this cell system.
Marcellus
R
R
Department of Microbiology and Immunology, Queen's University, Kingston, Ontario, Canada.
Whitfield
J F
JF
Raptis
L
L
D019870:1-Phosphatidylinositol 4-Kinase; D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000502:physiology*; D002460:Cell Line; D002461:Cell Line, Transformed; D002462:Cell Membrane / Q000201:enzymology / Q000648:ultrastructure; D002471:Cell Transformation, Neoplastic; D004789:Enzyme Activation / Q000502:physiology; D008565:Membrane Proteins / Q000378:metabolism / Q000502:physiology*; D015688:Oncogene Protein pp60(v-src) / Q000502:physiology; D010641:Phenotype; D010770:Phosphotransferases / Q000378:metabolism / Q000502:physiology*; D011493:Protein Kinase C / Q000378:metabolism / Q000502:physiology*
D000952:Antigens, Polyomavirus Transforming; D008565:Membrane Proteins; D010770:Phosphotransferases; D019870:1-Phosphatidylinositol 4-Kinase; D015688:Oncogene Protein pp60(v-src); D011493:Protein Kinase C