Functional counterparts of mammalian protein kinases PDK1 and SGK in budding yeast
Functional counterparts of mammalian protein kinases PDK1 and SGK in budding yeast
复制标题
DOI：
10.1016/s0960-9822(99)80088-8
复制
发表时间：
1999-02-25
期刊：
影响因子：
9.2
通讯作者：
Alessi, DR
中科院分区：
文献类型：
--
作者：
Casamayor, A;Torrance, PD;Alessi, DR
背景：在动物细胞中，生长因子受体募集磷脂酰肌醇 3-激酶产生 3-磷酸肌醇，刺激 3-磷酸肌醇依赖性蛋白激酶-1 (PDK1)。激活的 PDK1 然后磷酸化并激活下游蛋白激酶，包括蛋白激酶 B (PKB)/c-Akt、p70 S6 激酶、PKC 亚型以及血清和糖皮质激素诱导激酶 (SGK)，从而引发生理反应。结果：我们发现了两个以前未表征的酵母菌基因 酿酒酵母（我们称之为 PKH1 和 PKH2）编码的蛋白激酶具有与人类和果蝇 PDK1 非常相似的催化结构域。 Pkh1 和 Pkh2 对于细胞活力都至关重要。在原本无法存活的 pkh1 Delta pkh2 Delta 细胞中表达人 PDK1 可以使其生长。此外，还发现酵母 YPK1 和 YKR2 基因编码蛋白激酶，每个蛋白激酶的催化结构域与 SGK 非常相似。 Ypk1 和 Ykr2 对于生存能力也是必需的，否则无法存活的 ypk1 Delta ykr2 Delta 细胞可通过表达大鼠 SGK 而完全获救，但不能通过表达小鼠 PKB 或大鼠 p70 S6 激酶，纯化的 Pkh1 通过磷酸化与 PDK1 相同的残基，在体外激活哺乳动物 SGK 和 PKB α。 Pkh1 通过磷酸化等效残基 (Thr504) 来激活纯化的 Ypk1，并且是体内最大 Ypk1 磷酸化所必需的。与 PKB 不同，Pkh1 激活 Ypk1 和 SGK 不需要磷脂酰肌醇 3,4,5-三磷酸，这与这些蛋白质中不存在 pleckstrin 同源结构域一致。 Ypk1 的磷酸化共有序列与 PKB α 和 SGK 的磷酸化共有序列相似。结论：Pkh1 和 Pkh2 的功能与 PDK1 相似，Ypk1 和 Ykr2 的功能与 SGK 相似。与在动物细胞中一样，这两组酵母激酶构成了酵母细胞生长所需的两层信号级联。
Background: In animal cells, recruitment of phosphatidylinositol 3-kinase by growth factor receptors generates 3-phosphoinositides, which stimulate 3-phosphoinositide-dependent protein kinase-1 (PDK1). Activated PDK1 then phosphorylates and activates downstream protein kinases, including protein kinase B (PKB)/c-Akt, p70 S6 kinase, PKC isoforms, and serum- and glucocorticoid-inducible kinase (SGK), thereby eliciting physiological responses.Results: We found that two previously uncharacterised genes of Saccharomyces cerevisiae, which we term PKH1 and PKH2, encode protein kinases with catalytic domains closely resembling those of human and Drosophila PDK1. Both Pkh1 and Pkh2 were essential for cell viability. Expression of human PDK1 in otherwise inviable pkh1 Delta pkh2 Delta cells permitted growth. In addition, the yeast YPK1 and YKR2 genes were found to encode protein kinases each with a catalytic domain closely resembling that of SGK; both Ypk1 and Ykr2 were also essential for viability, Otherwise inviable ypk1 Delta ykr2 Delta cells were fully rescued by expression of rat SGK, but not mouse PKB or rat p70 S6 kinase, Purified Pkh1 activated mammalian SGK and PKB alpha in vitro by phosphorylating the same residue as PDK1. Pkh1 activated purified Ypk1 by phosphorylating the equivalent residue (Thr504) and was required for maximal Ypk1 phosphorylation in vivo. Unlike PKB, activation of Ypk1 and SGK by Pkh1 did not require phosphatidylinositol 3,4,5-trisphosphate, consistent with the absence of pleckstrin homology domains in these proteins. The phosphorylation consensus sequence for Ypk1 was similar to that for PKB alpha and SGK.Conclusions: Pkh1 and Pkh2 function similarly to PDK1, and Ypk1 and Ykr2 to SGK. As in animal cells, these two groups of yeast kinases constitute two tiers of a signalling cascade required for yeast cell growth.