Palmitoylation Is Required for Signaling Functions and Membrane Attachment of G,a and G,a*
Palmitoylation Is Required for Signaling Functions and Membrane Attachment of G,a and G,a*
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G,a 和 G,a* 的信号传导功能和膜附着需要棕榈酰化
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发表时间：
2001
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影响因子：
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通讯作者：
BourneS
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作者：
P. Wedegaertner;David H. ChuS;Paul T. Wilsonn;M. Levis;Henry;BourneS
我们已经确定了棕榈酰化半胱氨酸残基的a，和作为，两个异源三聚体G蛋白的亚基。丝氨酸突变取代a中的半胱氨酸9和10以及a中的半胱氨酸3，深刻地改变了HEK 293细胞中表达的亚基的行为。突变体a亚基均不包含棕榈酸酯;两种突变体蛋白质均存在于可溶性部分而非颗粒部分中;突变体a或a。不能将共表达的受体分别与磷脂酶C或腺苷酸环化酶的刺激偶联;半胱氨酸取代阻止突变激活的as（R183 C）直接刺激磷脂酶C，并降低但不消除类似激活的a.（R201 C）以刺激CAMP合成。肉豆蔻酰化序列取代棕榈酰化位点导致a和a被肉豆蔻酸酯而不是棕榈酸酯标记。肉豆蔻酰化恢复了非棕榈酰化的aq和α 1附着于膜的能力，并且在α 1的情况下，恢复了其刺激磷脂酶C的能力，无论是由R183 C穆塔还是由受体激活触发。这些发现确定棕榈酰化是q和a膜附着的关键决定因素，并表明这种修饰是正常信号传导所必需的，
We have identified the palmitoylated cysteine resi- dues of a, and as, a subunits of two heterotrimeric G proteins. Mutational substitutions of serines for cys- teines 9 and 10 in a, and cysteine 3 in a, profoundly alter behavior of the subunits expressed in HEK293 cells. Nei- ther mutant a subunit incorporates palmitate; both mutant proteins are found in the soluble rather than the particulate fraction; mutant a, or a. cannot couple a co-expressed receptor to stimulation of phospholipase C or adenylylcyclase, respectively; cysteine substitution prevents a mutationally activated as (R183C) from stimulating phospholipase C directly, and reduces but does not abolish the ability of a similarly activated a. (R201C) to stimulate CAMP synthesis. Substitution of a myristoylation sequence for the palmitoylation sites leads to labeling of a, and a, by myristate, rather than by palmitate. Myristoylation restores the abilities of both nonpalmitoylated aq and a, to attach to membranes and, in the case of a,, restores its ability to stimulate phospholipase C, whether triggered by the R183C muta- tion or by receptor activation. These findings identify palmitoylation as a critical determinant of membrane attachment for q and a, and show that this modification is required for normal signaling by