A novel motif at the C-terminus of palmitoyltransferases is essential for Swf1 and Pfa3 function in vivo
A novel motif at the C-terminus of palmitoyltransferases is essential for Swf1 and Pfa3 function in vivo
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DOI：
10.1042/bj20080921
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发表时间：
2009-04-15
影响因子：
4.1
通讯作者：
Valdez Taubas, Javier
中科院分区：
文献类型：
--
作者：
Gonzalez Montoro, Ayelen;Quiroga, Rodrigo;Valdez Taubas, Javier
S-酰化（通常称为棕榈酰化）是一种广泛的翻译后修饰，包括通过硫酯键将脂质分子添加到蛋白质的半胱氨酸残基上。这种修饰主要由称为PAT（棕榈酰转移酶）的蛋白质家族介导。大多数PAT是多位膜蛋白，具有4至6个跨膜结构域，保守的DHHC基序和可变的C-和N-末端区域，这可能是负责赋予定位和底物特异性。关于PAT的结构-功能关系的额外信息很少。Swf 1和Pfa 3是DHHC蛋白家族的酵母成员。Swf 1负责几种跨膜SNARE（可溶性N-乙基马来酰亚胺敏感性融合蛋白-附着蛋白受体）和其他整合膜蛋白的S-酰化。Pfa 3是参与液泡融合的蛋白质Vac 8棕榈酰化所必需的。在本研究中，我们描述了一种新的16个氨基酸的基序存在于PAT的胞质C-末端，这是所需的Swf 1和Pfa 3在体内的功能。在这个基序中，我们已经确定了Swf 1中的一个残基，Tyr（323），作为功能所必需的，这与缺乏TIg 1的棕榈酰化有关，TIg 1是Swf 1的底物。Pfa 3中的等同突变也影响其功能。对于这些或任何其他PAT，这些突变是第一个发现的不位于DHHC结构域内的影响表型的突变。该基序在所有分析的真核生物中70%的PAT中是保守的，并且可能曾经存在于所有PAT中。我们将该基序命名为PaCCT（“棕榈酰转移酶保守的C-末端”）。
S-acylation (commonly known as palmitoylation) is a widespread post-translational modification that consists of the addition of a lipid molecule to cysteine residues of a protein through a thioester bond. This modification is predominantly mediated by a family of proteins referred to as PATs (palmitoyltransferases). Most PATs are polytopic membrane proteins, with four to six transmembrane domains, a conserved DHHC motif and variable C-and N-terminal regions, that are probably responsible for conferring localization and substrate specificity. There is very little additional information on The structure-function relationship of PATs. Swf1 and Pfa3 are yeast members of the DHHC family of proteins. Swf1 is responsible for the S-acylation of several transmembrane SNAREs (soluble N-ethylmaleimide-sensitive fusion protein-attachment protein receptors) and other integral membrane proteins. Pfa3 is required for the palmitoylation of Vac8, a protein involved in vacuolar fusion. In the present study we describe a novel 16-amino-acid motif present at the cytosolic C-terminus of PATs, that is required for Swf1 and Pfa3 function in vivo. Within this motif, we have identified a single residue in Swf1, Tyr(323), as essential for function, and this is correlated with lack of palmitoylation of TIg1, a SNARE that is a substrate of Swf1. The equivalent mutation in Pfa3 also affects its function. These mutations are the first phenotype-affecting mutations uncovered that do not lie within the DHHC domain, for these or any other PATs. The motif is conserved in 70% of PATs from all eukaryotic organisms analysed, and may have once been present in all PATs. We have named this motif PaCCT ('Palmitoyltransferase Conserved C-Terminus').