Siciliano J C, Toutant M, Derkinderen P, Sasaki T, Girault J A
INSERM U 114, Chaire de Neuropharmacologie, Collège de France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05, France.
J Biol Chem. 1996 Nov 15;271(46):28942-6. doi: 10.1074/jbc.271.46.28942.
The mechanisms by which stimuli that raise cytosolic free Ca2+ concentrations in neurons can increase protein tyrosine phosphorylation are not known. Using rat hippocampal slices and cortical synaptosomes, we have examined the regulation of two highly related cytoplasmic tyrosine kinases, pp125 focal adhesion kinase (pp125(FAK)) and proline-rich tyrosine kinase 2/cell adhesion kinase beta (PYK2/CAKbeta). Membrane depolarization increased tyrosine phosphorylation of PYK2/CAKbeta and pp125(FAK). These effects were blocked by EGTA or by protein kinase C inhibitors (RO31-8220; GF109203X) and mimicked by ionomycin or phorbol 12-myristate 13-acetate, in the case of pp125(FAK), or their combination in the case of PYK2/CAKbeta. Glutamate and specific agonists of ionotropic (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate and N-methyl-D-aspartate) or metabotropic (trans-1-aminocyclopentane-1,3, -dicarboxylate) glutamate receptors stimulated the phosphorylation of pp125(FAK), but not of PYK2/CAKbeta. Glutamate effects were prevented by GF109203X. Thus, in hippocampal slices, tyrosine phosphorylation of pp125(FAK) and PYK2/CAKbeta are regulated differentially by pathways involving Ca2+ and protein kinase C. pp125(FAK) and PYK2/CAKbeta may provide specific links between neuronal activity, increases in cytosolic Ca2+ and protein tyrosine phosphorylation, which may be important for neuronal survival, and synaptic plasticity.
神经元中能提高胞质游离钙离子浓度的刺激因素增加蛋白质酪氨酸磷酸化的机制尚不清楚。利用大鼠海马切片和皮质突触体，我们研究了两种高度相关的胞质酪氨酸激酶，即125kDa粘着斑激酶（pp125(FAK)）和富含脯氨酸的酪氨酸激酶2/细胞粘着激酶β（PYK2/CAKβ）的调节情况。膜去极化增加了PYK2/CAKβ和pp125(FAK)的酪氨酸磷酸化。这些效应被乙二醇双四乙酸（EGTA）或蛋白激酶C抑制剂（RO31-8220；GF109203X）阻断，对于pp125(FAK)，离子霉素或佛波醇12-肉豆蔻酸酯13-乙酸酯可模拟这些效应，对于PYK2/CAKβ，则是它们的联合作用可模拟这些效应。离子型（α-氨基-3-羟基-5-甲基-4-异恶唑丙酸和N-甲基-D-天冬氨酸）或代谢型（反式-1-氨基环戊烷-1,3-二羧酸）谷氨酸受体的谷氨酸和特异性激动剂刺激了pp125(FAK)的磷酸化，但未刺激PYK2/CAKβ的磷酸化。GF109203X可阻止谷氨酸的效应。因此，在海马切片中，pp125(FAK)和PYK2/CAKβ的酪氨酸磷酸化受涉及钙离子和蛋白激酶C的途径的不同调节。pp125(FAK)和PYK2/CAKβ可能在神经元活动、胞质钙离子增加和蛋白质酪氨酸磷酸化之间提供特定联系，这可能对神经元存活和突触可塑性很重要。
