TOR1 AND TOR2 ARE STRUCTURALLY AND FUNCTIONALLY SIMILAR BUT NOT IDENTICAL PHOSPHATIDYLINOSITOL KINASE HOMOLOGS IN YEAST
TOR1 AND TOR2 ARE STRUCTURALLY AND FUNCTIONALLY SIMILAR BUT NOT IDENTICAL PHOSPHATIDYLINOSITOL KINASE HOMOLOGS IN YEAST
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DOI：
10.1091/mbc.5.1.105
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发表时间：
1994-01-01
影响因子：
3.3
通讯作者：
HALL, MN
中科院分区：
文献类型：
--
作者：
HELLIWELL, SB;WAGNER, P;HALL, MN
酿酒酵母基因TOR1和TOR2最初是通过对免疫抑制剂雷帕霉素产生抗药性的突变来鉴定的。先前研究表明，TOR2编码一个必需的282 kDa磷脂酰肌醇激酶(PI激酶)同系物。TOR1基因产物也是一个大的(281 KDa)PI激酶同源物，与TOR2有67%的同源性。TOR1不是必需的，但TOR1和TOR2的双重干扰独特地导致细胞周期(G1)停滞，就像接触雷帕霉素一样；TOR2的单独干扰是致命的，但不会导致细胞周期停滞。TOR1-TOR2和TOR2-TOR1杂交种表明，TOR1和TOR2的羧基末端结构域含有脂蛋白激酶序列基序，可以互换，因此功能相同；TOR1和TOR2的其他部分不能互换。TOR1-1和TOX2-1突变导致雷帕霉素耐药，改变了各自蛋白质脂蛋白激酶域中相同的潜在蛋白激酶C位点。因此，TOR1和TOR2可能是相似但不完全相同的，雷帕霉素敏感的PI激酶可能受磷酸化调节。TOR1和TOR2可能是控制G1进程的新的信号转导通路的组成部分。
The Saccharomyces cerevisiae genes TOR1 and TOR2 were originally identified by mutations that confer resistance to the immunosuppressant rapamycin. TOR2 was previously shown to encode an essential 282-kDa phosphatidylinositol kinase (PI kinase) homologue. The TOR1 gene product is also a large (281 kDa) PI kinase homologue, with 67% identity to TOR2. TOR1 is not essential, but a TOR1 TOR2 double disruption uniquely confers a cell cycle (G1) arrest as does exposure to rapamycin; disruption of TOR2 alone is lethal but does not cause a cell cycle arrest. TOR1-TOR2 and TOR2-TOR1 hybrids indicate that carboxy-terminal domains of TOR1 and TOR2 containing a lipid kinase sequence motif are interchangeable and therefore functionally equivalent; the other portions of TOR1 and TOR2 are not interchangeable. The TOR1-1 and TOX2-1 mutations, which confer rapamycin resistance, alter the same potential protein kinase C site in the respective protein's lipid kinase domain. Thus, TOR1 and TOR2 are likely similar but not identical, rapamycin-sensitive PI kinases possibly regulated by phosphorylation. TOR1 and TOR2 may be components of a novel signal transduction pathway controlling progression through G1.