At the onset of transformation polyomavirus middle-T recruits shc and src to a perinuclear compartment coincident with condensation of endosomes.
To examine the early cellular changes that accompany transformation, middle-T antigen (the transforming protein of polyomavirus), was expressed from an inducible promoter in Rat2 fibroblasts and in normal diploid human fibroblast (MRC5) cells using a replication defective adenovirus vector. The earliest detectable expression of middle-T antigen correlated closely with the initial changes in cellular morphology. At this time, expression of middle-T antigen resulted in the redistribution of shc and src to a brefeldin A resistant perinuclear compartment coincident with the formation of kinase active complexes containing middle-T antigen, shc and src. The first detectable changes directly related to altered morphology was reorganization of actin filaments, and the condensation of tubular endosomes in the perinuclear region of the cell. These results suggest a potential role for perinuclear localized mT molecules in some of the morphologic changes associated with the initial phase of cellular transformation.
Department of Biochemistry, McMaster University, Hamilton, Ontario, Canada.
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D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000260:Adenoviruses, Human; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000952:Antigens, Polyomavirus Transforming / Q000235:genetics / Q000378:metabolism*; D020126:Brefeldin A; D002451:Cell Compartmentation; D002460:Cell Line; D002461:Cell Line, Transformed; D002467:Cell Nucleus / Q000378:metabolism; D002472:Cell Transformation, Viral; D003517:Cyclopentanes / Q000494:pharmacology; D011992:Endosomes / Q000502:physiology*; D005822:Genetic Vectors; D006801:Humans; D018942:Macrolides; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D018909:src Homology Domains
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000900:Anti-Bacterial Agents; D000952:Antigens, Polyomavirus Transforming; D003517:Cyclopentanes; D018942:Macrolides; D011500:Protein Synthesis Inhibitors; D011506:Proteins; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; C528035:Shc1 protein, rat; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D020126:Brefeldin A