Yeast glycogen synthase kinase-3 activates Msn2p-dependent transcription of stress responsive genes
Yeast glycogen synthase kinase-3 activates Msn2p-dependent transcription of stress responsive genes
复制标题
DOI：
10.1091/mbc.e02-05-0247
复制
发表时间：
2003-01-01
影响因子：
3.3
通讯作者：
Kikuchi, A
中科院分区：
文献类型：
--
作者：
Hirata, Y;Andoh, T;Kikuchi, A
酵母有MCK1、MDS1 （RIM11）、MRK1和YOL128c四个基因编码哺乳动物糖原合成酶激酶3 （GSK-3）的同源物。这四个基因被破坏的gsk-3零突变体在半乳糖培养基上表现出生长缺陷。我们分离出这种生长缺陷的几个多拷贝抑制因子。其中2个编码Msn2p和磷酸葡萄糖糖化酶（PGM）。Msn2p是一种结合应激反应元件（STRE）的转录因子。PGM是一种相互转化葡萄糖-1磷酸和葡萄糖-6磷酸的酶，在转录水平上受Msn2p的调控。在热休克或盐胁迫诱导下，启动子区含有STRE序列的PGM2和DDR2 mrna的表达不仅在msn2 - msn4 （msn2同系物）双突变体中减少，而且在gsk-3零突变体中也减少。在gsk-3零突变体或mck1 mds1双突变体中，stret依赖的转录被极大地抑制，这种表型被Mck1p的表达抑制，而不被激酶无活性形式的Mck1p抑制。尽管在各种胁迫条件下，Msn2p在gsk-3零突变体和野生型菌株的细胞核中积累，但在gsk-3零突变体或mck1 mds1双突变体的提取物中，其stret结合活性降低。这些结果表明，酵母GSK-3促进Msn2p和DNA之间复合物的形成，这是对不同形式的应激作出适当反应所必需的。由于既没有检测到Msn2p-GSK-3复合物的形成，也没有检测到GSK-3依赖性的Msn2p磷酸化，因此GSK-3对Msn2p的调控可能是间接的。
The yeast Saccharomyces cerevisiae has four genes, MCK1, MDS1 (RIM11), MRK1, and YOL128c, that encode homologues of mammalian glycogen synthase kinase 3 (GSK-3). A gsk-3 null mutant in which these four genes are disrupted showed growth defects on galactose medium. We isolated several multicopy suppressors of this growth defect. Two of them encoded Msn2p and phosphoglucomutase (PGM). Msn2p is a transcription factor that binds to the stress-response element (STRE). PGM is an enzyme that interconverts glucose-1 phosphate and glucose-6 phosphate and is regulated by Msn2p at the transcriptional level. Expression of the mRNAs of PGM2 and DDR2, whose promoter regions possess STRE sequences, on induction by heat shock or salt stress was reduced not only in an msn2 msn4 (msn2 homologue) double mutant but also in the gsk-3 null mutant. STRE-dependent transcription was greatly inhibited in the gsk-3 null mutant or mck1 mds1 double mutant, and this phenotype was suppressed by the expression of Mck1p but not of a kinase-inactive form of Mck1p. Although Msn2p accumulated in the nucleus of the gsk-3 null mutant as well as in the wild-type strain under various stress conditions, its STRE-binding activity was reduced in extracts prepared from the gsk-3 null mutant or mck1 mds1 double mutant. These results suggest that yeast GSK-3 promotes formation of a complex between Msn2p and DNA, which is required for the proper response to different forms of stress. Because neither Msn2p-GSK-3 complex formation nor GSK-3-dependent phosphorylation of Msn2p could be detected, the regulation of Msn2p by GSK-3 may be indirect.