Phosphorylation of golgin-160 by mixed lineage kinase 3
Phosphorylation of golgin-160 by mixed lineage kinase 3
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DOI：
10.1242/jcs.00897
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发表时间：
2004-02-15
影响因子：
4
通讯作者：
Shapiro, P
中科院分区：
文献类型：
--
作者：
Cha, H;Smith, BL;Shapiro, P
Golgin-160 是高尔金蛋白卷曲螺旋家族的成员，其被认为可以调节高尔基复合体的结构。 golgin-160 的 C 端三分之二预计会形成卷曲螺旋结构域，N 端头结构域包含几个假定的结合结构域、调节基序和磷酸化位点。最近，已经证明，在诱导细胞凋亡后，golgin-160 头结构域的 caspase 依赖性裂解迅速发生。 golgin-160 磷酸化的作用以及对高尔基体结构的功能影响尚未明确。在这项研究中，我们研究了负责 golgin-160 磷酸化的激酶。通过小 G 蛋白 Rac 和混合谱系激酶 3 (MLK3) 的信号传导导致 golgin-160 磷酸化增加。 MLK3与golgin-160在细胞内的分布重叠，两种蛋白可以进行免疫共沉淀。体外激酶测定表明，MLK3 直接磷酸化残基 96 和 259 之间 N 端头区域的 golgin-160。MLK3 的过度表达导致 golgin-160 在 Asp139 处的 caspase 依赖性裂解增强。 Golgin-160 是第一个被鉴定的 MLK3 非激酶底物，MLK3 的磷酸化可能会在细胞凋亡过程中调节 golgin-160 的裂解。
Golgin-160 is a member of the coiled-coil family of golgin proteins, which are proposed to regulate the structure of the Golgi complex. The C-terminal two-thirds of golgin-160 is predicted to form a coiled-coil domain and the N-terminal head domain contains several putative binding domains, regulatory motifs and phosphorylation sites. Recently, it has been demonstrated that caspase-dependent cleavage of the golgin-160 head domain occurs rapidly after induction of apoptosis. The role of golgin-160 phosphorylation and the functional implications for Golgi structure have not been defined. In this study, we investigated the kinase(s) responsible for phosphorylation of golgin-160. Signaling through the small G-protein Rac and mixed-lineage-kinase-3 (MLK3) resulted in increased phosphorylation of golgin-160. The intracellular distribution of MLK3 overlapped with that of golgin-160 and the two proteins could be co-immunoprecipitated. In vitro kinase assays demonstrated that MLK3 directly phosphorylates golgin-160 in the N-terminal head region between residues 96 and 259. Overexpression of MLK3 caused an enhanced caspase-dependent cleavage of golgin-160 at Asp139. Golgin-160 is the first non-kinase substrate of MLK3 identified, and phosphorylation by MLK3 might modulate cleavage of golgin-160 during apoptosis.