Wang X, Hoekstra M F, DeMaggio A J, Dhillon N, Vancura A, Kuret J, Johnston G C, Singer R A
Department of Biochemistry, Dalhousie University, Halifax, Nova Scotia, Canada.
Mol Cell Biol. 1996 Oct;16(10):5375-85. doi: 10.1128/MCB.16.10.5375.
The GCS1 gene of the budding yeast Saccharomyces cerevisiae mediate the resumption of cell proliferation from the starved, stationary-phase state. Here we identify yeast genes that, in increased dosages, overcome the growth defect of gcs1 delta mutant cells. Among these are YCK1 (CK12) and YCK2 (CKI1), encoding membrane-associated casein kinase I, and YCK3, encoding a novel casein kinase I isoform. Some Yck3p gene product was found associated with the plasma membrane, like Yck1p and Yck2p, but most confractionated with the nucleus, like another yeast casein kinase I isoform, Hrr25p. Genetic studies showed that YCK3 and HRR25 constitute an essential gene family and that Yck3p can weakly substitute for Yck1p-Yck2p. For gcs1 delta suppression, both a protein kinase domain and a C-terminal prenylation motif were shown to be necessary. An impairment in endocytosis was found for gcs1 delta mutant cells, which was alleviated by an increased YCK2 gene dosage. The ability of an increased casein kinase I gene dosage to suppress the effects caused by the absence of Gcs1p suggests that Gcs1p and Yck1p-Yck2p affect parallel pathways.
芽殖酵母酿酒酵母的GCS1基因介导细胞从饥饿的静止期状态恢复增殖。在此，我们鉴定了一些酵母基因，当它们的剂量增加时，能够克服gcs1δ突变细胞的生长缺陷。其中包括YCK1（CK12）和YCK2（CKI1），它们编码与膜相关的酪蛋白激酶I，以及YCK3，它编码一种新型的酪蛋白激酶I亚型。发现一些Yck3p基因产物与质膜相关，如Yck1p和Yck2p，但大多数与细胞核一起分级分离，就像另一种酵母酪蛋白激酶I亚型Hrr25p一样。遗传学研究表明，YCK3和HRR25构成一个必需基因家族，并且Yck3p可以微弱地替代Yck1p - Yck2p。对于gcs1δ抑制，蛋白激酶结构域和C末端异戊二烯化基序都被证明是必需的。发现gcs1δ突变细胞存在内吞作用缺陷，增加YCK2基因剂量可缓解这一缺陷。酪蛋白激酶I基因剂量增加抑制Gcs1p缺失所产生效应的能力表明，Gcs1p和Yck1p - Yck2p影响平行途径。
