title: Translocation of PKC isoforms in bovine aortic smooth muscle cells exposed to strain.
abstract: Our laboratory has previously reported that the exposure of smooth muscle cells (SMC) to the cyclic strain results in significant stimulation of protein kinase C (PKC) activity by translocating the enzyme from the cytosol to the particulate fraction. We now sought to examine the strain-induced translocation of individual PKC isoforms in SMC. Confluent bovine aortic SMC grown on collagen type I-coated plates were exposed to cyclic strain for up to 100 s at average 10% strain with 60 cycles/min. Immunoblotting analysis demonstrates that SMC express PKC-alpha, -beta and -zeta in both cytosolic and particulate fractions. Especially, PKC-alpha and -zeta were predominantly expressed in the cytosolic fraction. However, cyclic strain significantly (P < 0.05) increased PKC-alpha and -zeta in the particulate fraction and decreased in the cytosolic fraction. Thus, the cyclic strain-mediated stimulation of PKC activity in SMC may be due to the translocation of PKC-alpha and -zeta from the cytosolic to the particulate fraction. These results demonstrate that mechanical deformation causes rapid translocation of PKC isoforms, which may initiate a cascade of proliferation responses of SMC since NF-kappaB, which is involved in the cellular proliferation has been known to be activated by these PKC isoforms.
authors.affiliation: Department of Surgery, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
authors.forename: O
authors.initials: O
authors.lastname: Han
authors.forename: T
authors.initials: T
authors.lastname: Takei
authors.forename: M
authors.initials: M
authors.lastname: Basson
authors.forename: B E
authors.initials: BE
authors.lastname: Sumpio
mesh_terms: D000818:Animals; D001011:Aorta / Q000201:enzymology*; D002417:Cattle; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000201:enzymology*; D011493:Protein Kinase C / Q000378:metabolism*; D021381:Protein Transport
chemical_list: D007527:Isoenzymes; D011493:Protein Kinase C