The yeast Sks1p kinase signaling network regulates pseudohyphal growth and glucose response.
The yeast Sks1p kinase signaling network regulates pseudohyphal growth and glucose response.
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DOI：
10.1371/journal.pgen.1004183
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发表时间：
2014-03
期刊：
影响因子：
4.5
通讯作者：
Kumar A
中科院分区：
文献类型：
--
作者：
Johnson C;Kweon HK;Sheidy D;Shively CA;Mellacheruvu D;Nesvizhskii AI;Andrews PC;Kumar A
酿酒酵母经历了从单细胞形态到丝状状态的戏剧性生长转变，其特征是由细长和连接的细胞形成假菌丝。酵母假菌丝的生长受到响应氮和葡萄糖可用性降低的信号通路的调节，但假菌丝丝和葡萄糖信号传导之间的分子联系尚不完全清楚。在这里，我们发现葡萄糖敏感的Sks1p激酶是氮限制和氮/葡萄糖偶联限制诱导的假菌丝生长所需的信号蛋白。为了确定Sks1p信号网络，我们应用了基于质谱的定量磷酸化蛋白质组学，分析了900多个磷酸化位点依赖于Sks1p激酶活性的磷酸化变化。从这一分析中，我们报告了一组新的磷酸化位点，并强调了Bud6p、Itr1p、Lrg1p、Npr3p和Pda1p中sks1p依赖的磷酸化。我们特别分析了丙酮酸脱氢酶亚基Pda1p中的Y309和S313磷酸基；这些残基是假菌丝生长所必需的，Y309A突变体表现出有氧呼吸受损和线粒体数量减少的表型。上位性研究认为SKS1位于g蛋白偶联受体GPR1和g蛋白RAS2的下游，但位于camp依赖性PKA的上游或水平。假菌丝生长和葡萄糖信号转录因子Flo8p、Mss11p和Rgt1p是达到野生型SKS1转录水平所必需的。SKS1是保守的，白色念珠菌中SKS1同源基因SHA3的缺失会导致菌落形态异常。总的来说，这些结果确定Sks1p是丝化和葡萄糖信号传导的重要调节因子，对理解白色念珠菌的应激反应信号传导具有额外的相关性。真核细胞通过控制细胞代谢、生长和形态的复杂调控程序来应对营养和环境胁迫。在出芽酵母中，有限的氮和/或葡萄糖条件可以启动一个戏剧性的生长转变，其中酵母细胞形成类似于丝状真菌的真正菌丝管的延长的多细胞细丝。这些假菌丝的形成是由核心调控途径控制的，已经研究了几十年；然而，这些信号系统整合的机制尚不清楚。我们发现蛋白激酶Sks1p有助于氮和/或葡萄糖限制信号的整合，导致假菌丝生长。我们实施了一种基于质谱的方法来分析依赖于Sks1p激酶活性的蛋白质组磷酸化事件，并确定了对线粒体功能和假菌丝生长重要的磷酸化位点。我们的研究将Sks1p置于一个众所周知的假菌丝生长信号通路的调控环境中。我们进一步发现SKS1是保守的，并且在主要的机会性人类真菌病原体白色念珠菌的应激反应菌落形态中是必需的。因此，Sks1p是整合葡萄糖应答细胞信号和假菌丝生长机制的一部分，其功能是与白色念珠菌毒力相关的菌落形态所必需的。
The yeast Saccharomyces cerevisiae undergoes a dramatic growth transition from its unicellular form to a filamentous state, marked by the formation of pseudohyphal filaments of elongated and connected cells. Yeast pseudohyphal growth is regulated by signaling pathways responsive to reductions in the availability of nitrogen and glucose, but the molecular link between pseudohyphal filamentation and glucose signaling is not fully understood. Here, we identify the glucose-responsive Sks1p kinase as a signaling protein required for pseudohyphal growth induced by nitrogen limitation and coupled nitrogen/glucose limitation. To identify the Sks1p signaling network, we applied mass spectrometry-based quantitative phosphoproteomics, profiling over 900 phosphosites for phosphorylation changes dependent upon Sks1p kinase activity. From this analysis, we report a set of novel phosphorylation sites and highlight Sks1p-dependent phosphorylation in Bud6p, Itr1p, Lrg1p, Npr3p, and Pda1p. In particular, we analyzed the Y309 and S313 phosphosites in the pyruvate dehydrogenase subunit Pda1p; these residues are required for pseudohyphal growth, and Y309A mutants exhibit phenotypes indicative of impaired aerobic respiration and decreased mitochondrial number. Epistasis studies place SKS1 downstream of the G-protein coupled receptor GPR1 and the G-protein RAS2 but upstream of or at the level of cAMP-dependent PKA. The pseudohyphal growth and glucose signaling transcription factors Flo8p, Mss11p, and Rgt1p are required to achieve wild-type SKS1 transcript levels. SKS1 is conserved, and deletion of the SKS1 ortholog SHA3 in the pathogenic fungus Candida albicans results in abnormal colony morphology. Collectively, these results identify Sks1p as an important regulator of filamentation and glucose signaling, with additional relevance towards understanding stress-responsive signaling in C. albicans. Eukaryotic cells respond to nutritional and environmental stress through complex regulatory programs controlling cell metabolism, growth, and morphology. In the budding yeast Saccharomyces cerevisiae, conditions of limited nitrogen and/or glucose can initiate a dramatic growth transition wherein the yeast cells form extended multicellular filaments resembling the true hyphal tubes of filamentous fungi. The formation of these pseudohyphal filaments is governed by core regulatory pathways that have been studied for decades; however, the mechanism by which these signaling systems are integrated is less well understood. We find that the protein kinase Sks1p contributes to the integration of signals for nitrogen and/or glucose limitation, resulting in pseudohyphal growth. We implemented a mass spectrometry-based approach to profile phosphorylation events across the proteome dependent upon Sks1p kinase activity and identified phosphorylation sites important for mitochondrial function and pseudohyphal growth. Our studies place Sks1p in the regulatory context of a well-known pseudohyphal growth signaling pathway. We further find that SKS1 is conserved and required for stress-responsive colony morphology in the principal opportunistic human fungal pathogen Candida albicans. Thus, Sks1p is part of the mechanism integrating glucose-responsive cell signaling and pseudohyphal growth, and its function is required for colony morphology linked with virulence in C. albicans.
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影响因子：
12.3
作者：
Geladé R;Van de Velde S;Van Dijck P;Thevelein JM
通讯作者：
Thevelein JM
影响因子：
14.9
作者：
Chatr-Aryamontri A;Breitkreutz BJ;Heinicke S;Boucher L;Winter A;Stark C;Nixon J;Ramage L;Kolas N;O'Donnell L;Reguly T;Breitkreutz A;Sellam A;Chen D;Chang C;Rust J;Livstone M;Oughtred R;Dolinski K;Tyers M
通讯作者：
Tyers M
DOI：
10.1073/pnas.88.21.9392
发表时间：
1991-11-01
影响因子：
11.1
作者：
ELION, EA;BRILL, JA;FINK, GR
通讯作者：
FINK, GR
影响因子：
3.3
作者：
Ahn, SH;Acurio, A;Kron, SJ
通讯作者：
Kron, SJ
影响因子：
--
作者：
Fortwendel, Jarrod R.;Juvvadi, Praveen R.;Steinbach, William J.
通讯作者：
Steinbach, William J.