First Author | Kawakami Y | Year | 2003 |
Journal | Proc Natl Acad Sci U S A | Volume | 100 |
Issue | 16 | Pages | 9470-5 |
PubMed ID | 12881490 | Mgi Jnum | J:84787 |
Mgi Id | MGI:2670234 | Doi | 10.1073/pnas.1633695100 |
Citation | Kawakami Y, et al. (2003) A Ras activation pathway dependent on Syk phosphorylation of protein kinase C. Proc Natl Acad Sci U S A 100(16):9470-5 |
abstractText | Protein kinase C (PKC) and Syk protein tyrosine kinase play critical roles in immune cell activation including that through the high-affinity IgE receptor, FcepsilonRI. Mechanisms by which PKC activation leads to the activation of Ras, a family of GTPases essential for immune cell activation, have been elusive. We present evidence that Tyr-662 and Tyr-658 of PKCbetaI and PKCalpha, respectively, are phosphorylated by Syk in the membrane compartment of FcepsilonRI-stimulated mast cells. These phosphorylations require prior PKC autophosphorylation of the adjacent serine residues (Ser-661 and Ser-657, respectively) and generate a binding site for the SH2 domain of the adaptor protein Grb-2. By recruiting the Grb-2/Sos complex to the plasma membrane, these conventional PKC isoforms contribute to the full activation of the Ras/extracellular signal-regulated kinase signaling pathway in FcepsilonRI-stimulated mast cells. |