Rebay I, Rubin G M
Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley 94720-3200, USA.
Cell. 1995 Jun 16;81(6):857-66. doi: 10.1016/0092-8674(95)90006-3.
Drosophila yan has been postulated to act as an antagonist of the proneural signal mediated by the sevenless/Ras1/MAPK pathway. We have mutagenized the eight MAPK phosphorylation consensus sites of yan and examined the effects of overexpressing the mutant protein in transgenic flies and transfected S2 cultured cells. Our results suggest that phosphorylation by MAPK affects the stability and subcellular localization of yan, resulting in rapid down-regulation of yan activity. Furthermore, MAPK-mediated down-regulation of yan function appears to be critical for the proper differentiation of both neuronal and nonneuronal tissues throughout development, suggesting that yan is an essential component of a general timing mechanism controlling the competence of a cell to respond to inductive signals.
果蝇的 yan 蛋白被推测作为由 sevenless/Ras1/MAPK 信号通路介导的神经前体信号的拮抗剂。我们对 yan 蛋白的八个 MAPK 磷酸化共有位点进行了诱变，并研究了在转基因果蝇和转染的 S2 培养细胞中过表达突变蛋白的影响。我们的结果表明，MAPK 介导的磷酸化作用影响了 yan 蛋白的稳定性和亚细胞定位，导致 yan 蛋白活性的快速下调。此外，MAPK 介导的 yan 蛋白功能下调对于整个发育过程中神经组织和非神经组织的正常分化似乎至关重要，这表明 yan 蛋白是控制细胞对诱导信号反应能力的一般时间调控机制的重要组成部分。
