Two NDR kinase-MOB complexes function as distinct modules during septum formation and tip extension in Neurospora crassa.
Two NDR kinase-MOB complexes function as distinct modules during septum formation and tip extension in Neurospora crassa.
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DOI：
10.1111/j.1365-2958.2009.06896.x
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发表时间：
2009-11
影响因子：
3.6
通讯作者：
Seiler S
中科院分区：
文献类型：
--
作者：
Maerz S;Dettmann A;Ziv C;Liu Y;Valerius O;Yarden O;Seiler S
NDR激酶对于生长和分化是重要的，并且需要与MOB蛋白相互作用以获得活性和功能。我们表征了粗糙脉孢菌中的NDR激酶和MOB激活剂，并鉴定了形成两种功能性NDR-MOB蛋白复合物的两种NDR激酶（COT 1和DBF 2）和四种MOB蛋白（MOB 1、MOB 2A、MOB 2B和MOB 3/phocein）。MOB 1-DBF 2复合物不仅在营养细胞中的隔膜形成和分生孢子形成过程中必不可少，而且在有性子实体发育和子囊孢子发生中也起作用。这两种MOB 2型蛋白与两种COT 1亚型相互作用，并通过调节COT 1活性来控制极尖延伸和分支。直接位于COT 1激酶结构域之前的保守区域足以形成COT 1-MOB 2异二聚体，但也足以形成激酶同源二聚体。一个额外的N-末端延伸，是保守性差，但目前在大多数真菌的NDR激酶，需要进一步稳定的两种类型的相互作用和刺激COT 1活性。缺乏该区域的COT 1在mob-2背景下降解。我们提出了一个特定的作用，MOB 3/phocein在营养细胞融合，子实体发育和子囊孢子形成是无关的其他三个MOB蛋白和NDR激酶信号。
NDR kinases are important for growth and differentiation and require interaction with MOB proteins for activity and function. We characterized the NDR kinases and MOB activators in Neurospora crassa and identified two NDR kinases (COT1 and DBF2) and four MOB proteins (MOB1, MOB2A, MOB2B and MOB3/phocein) that form two functional NDR–MOB protein complexes. The MOB1–DBF2 complex is not only essential for septum formation in vegetative cells and during conidiation, but also functions during sexual fruiting body development and ascosporogenesis. The two MOB2-type proteins interact with both COT1 isoforms and control polar tip extension and branching by regulating COT1 activity. The conserved region directly preceding the kinase domain of COT1 is sufficient for the formation of COT1–MOB2 heterodimers, but also for kinase homodimerization. An additional N-terminal extension that is poorly conserved, but present in most fungal NDR kinases, is required for further stabilization of both types of interactions and for stimulating COT1 activity. COT1 lacking this region is degraded in a mob-2 background. We propose a specific role of MOB3/phocein during vegetative cell fusion, fruiting body development and ascosporogenesis that is unrelated to the three other MOB proteins and NDR kinase signalling.