Scholz G, Felder M P, Hanafusa H
Laboratory of Molecular Oncology, Rockefeller University, New York, NY 10021, USA.
Proc Natl Acad Sci U S A. 1995 Mar 28;92(7):2592-6. doi: 10.1073/pnas.92.7.2592.
We have previously reported that a serine(threonine) protein kinase that phosphorylates histone H1 in vitro is activated by tyrosine phosphorylation in v-Src-transformed rat 3Y1 fibroblasts. We now refer to this kinase as YRP kinase, for tyrosine-regulated protein kinase. Since YRP kinase may play a role in mediating the growth-stimulatory and morphology-altering effects of v-Src, we have further examined the signal transduction involved in the activation of YRP kinase. Although YRP kinase is constitutively activated in fibroblasts transformed by v-Src, activation of protein kinase C was also found to lead to activation of YRP kinase. Activation of YRP kinase by protein kinase C was found to be potentiated by vanadate treatment or overexpression of c-Src. The activation of YRP kinase by v-Src, however, does not appear to be mediated by protein kinase C, suggesting that YRP kinase can be activated by two separate signal transduction pathways. Transformation of fibroblasts by v-Ras or v-Mil did not result in activation of YRP kinase, indicating that the MAP kinase pathway does not mediate the activation of YRP kinase by v-Src or protein kinase C.
我们之前报道过，一种在体外使组蛋白H1磷酸化的丝氨酸（苏氨酸）蛋白激酶，在v-Src转化的大鼠3Y1成纤维细胞中可被酪氨酸磷酸化激活。我们现在将这种激酶称为YRP激酶，即酪氨酸调节蛋白激酶。由于YRP激酶可能在介导v-Src的生长刺激和形态改变作用中发挥作用，我们进一步研究了YRP激酶激活过程中涉及的信号转导。虽然YRP激酶在v-Src转化的成纤维细胞中持续激活，但也发现蛋白激酶C的激活会导致YRP激酶的激活。发现钒酸盐处理或c-Src的过表达可增强蛋白激酶C对YRP激酶的激活作用。然而，v-Src对YRP激酶的激活似乎不是由蛋白激酶C介导的，这表明YRP激酶可通过两条独立的信号转导途径激活。v-Ras或v-Mil对成纤维细胞的转化并未导致YRP激酶的激活，这表明丝裂原活化蛋白激酶途径并不介导v-Src或蛋白激酶C对YRP激酶的激活。
