| First Author | Rucci N | Year | 2005 |
| Journal | J Cell Sci | Volume | 118 |
| Issue | Pt 15 | Pages | 3263-75 |
| PubMed ID | 16014375 | Mgi Jnum | J:175183 |
| Mgi Id | MGI:5284791 | Doi | 10.1242/jcs.02436 |
| Citation | Rucci N, et al. (2005) A novel protein kinase C alpha-dependent signal to ERK1/2 activated by alphaVbeta3 integrin in osteoclasts and in Chinese hamster ovary (CHO) cells. J Cell Sci 118(Pt 15):3263-75 |
| abstractText | We identified a novel protein kinase C (PKC)alpha-dependent signal to extracellular signal-regulated kinase (ERK)1/2 in mouse osteoclasts and Chinese hamster ovary (CHO) cells, specifically activated by the alphaVbeta3 integrin. It involves translocation (i.e. activation) of PKCalpha from the cytosol to the membrane and/or the Triton X-100-insoluble subcellular fractions, with recruitment into a complex with alphaVbeta3 integrin, growth factor receptor-bound protein (Grb2), focal adhesion kinase (FAK) in CHO cells and proline-rich tyrosine kinase (PYK2) in osteoclasts. Engagement of alphavbeta3 integrin triggered ERK1/2 phosphorylation, but the underlying molecular mechanism was surprisingly independent of the well known Shc/Ras/Raf-1 cascade, and of phosphorylated MAP/ERK kinase (MEK)1/2, so far the only recognized direct activator of ERK1/2. In contrast, PKCalpha was involved in ERK1/2 activation because inhibition of its activity prevented ERK1/2 phosphorylation. The tyrosine kinase c-Src also contributed to ERK1/2 activation, however, it did not interact with PKCalpha in the same molecular complex. The alphaVbeta3/PKCalpha complex formation was fully dependent upon the intracellular calcium concentration ([Ca2+]i), and the use of the intracellular Ca2+ chelator 1,2-bis(o-amino-phenoxy)ethane-N,N,N',N'-tetraaceticacidtetra (acetoxymethyl) ester (BAPTA-AM) also inhibited PKCalpha translocation and ERK1/2 phosphorylation. Functional studies showed that alphaVbeta3 integrin-activated PKCalpha was involved in cell migration and osteoclast bone resorption, but had no effect on the ability of cells to attach to LM609, suggesting a role in events downstream of alphaVbeta3 integrin engagement. |
