title: In vivo and in vitro association of hsc70 with polyomavirus capsid proteins.
abstract: Members of the 70-kDa family of cellular stress proteins assit in protein folding by preventing inappropriate intra- and intermolecular interactions during normal protein synthesis and transport and when cells are exposed to a variety of environmental stresses. During infection of A31 mouse fibroblasts with polyomavirus, the constitutive form of hsp70, hsc70, coimmunoprecipitated with all three viral capsid proteins (VP1, VP2, and VP3). In addition, the subcellular location of hsc70 changed from cytoplasmic to nuclear late in polyomavirus infection, coincident with the nuclear localization of the viral capsid proteins. VP1 and VP2 expressed in Sf9 insect cells with recombinant baculovirus vectors also coimmunoprecipitated with an hsp70-like protein, and VP1 expressed in Escherichia coli coimmunoprecipitated with the hsp70 homolog DnaK. Capsid proteins expressed by in vitro translation coimmunoprecipitated with the hsc70 protein present in the reticulocyte translation extract. Therefore, the polyomavirus capsid proteins associate with hsc70 during virus infection as well as in recombinant protein expression systems. This association may play a role in preventing the premature assembly of capsids in the cytosol and/or in facilitating the nuclear transport of capsid protein complexes.
mesh_terms: D016475:3T3 Cells; D000818:Animals; D001345:Autoradiography; D002213:Capsid / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D036022:Capsid Proteins; D002352:Carrier Proteins / Q000302:isolation & purification / Q000502:physiology*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli; D015870:Gene Expression; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D011120:Polyomavirus / Q000502:physiology*; D011485:Protein Binding; D014176:Protein Biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D018411:Spodoptera; D013462:Sulfur Radioisotopes; D014162:Transfection
chemical_list: D036022:Capsid Proteins; D002352:Carrier Proteins; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; C494372:Hspa8 protein, mouse; D011994:Recombinant Proteins; D013462:Sulfur Radioisotopes; C442543:VP2 protein, Polyomavirus