Phospholipid-stimulated autophosphorylation activates the G protein-coupled receptor kinase GRK5.
Phospholipid-stimulated autophosphorylation activates the G protein-coupled receptor kinase GRK5.
复制标题
DOI：
--
复制
发表时间：
1994-04
期刊：
影响因子：
--
通讯作者：
P. Kunapuli;V. Gurevich;Jeffrey L. Benovicz
中科院分区：
文献类型：
--
作者：
P. Kunapuli;V. Gurevich;Jeffrey L. Benovicz
G蛋白偶联受体激酶（GRKs）在介导多种G蛋白偶联受体的激动剂特异性脱敏中起重要作用。GRK5是最近发现的GRK家族成员，它经历了一个快速的磷脂刺激的自磷酸化，其化学计量值约为2mol磷酸/mol GRK5。磷脂刺激自磷酸化的能力在很大程度上被谷胱甘肽s -转移酶融合蛋白阻断，该融合蛋白含有GRK5的最后102个氨基酸（氨基酸489-590），这表明这是GRK5/磷脂相互作用的主要区域。磷酸氨基酸测定和诱变研究表明，GRK5的自磷酸化主要发生在Ser-484和Thr-485残基上。不进行自磷酸化的突变体GRK5 （S484A和T485A）的表达和表征表明，与野生型GRK5相比，该突变体磷酸化β 2-肾上腺素能受体和视紫红质的能力降低了约15-20倍。这些结果表明磷脂刺激的自磷酸化可能代表了一种新的膜关联和调控GRK5活性的机制。
G protein-coupled receptor kinases (GRKs) play an important role in mediating agonist-specific desensitization of numerous G protein-coupled receptors. GRK5, a recently identified member of the GRK family, undergoes a rapid phospholipid-stimulated autophosphorylation to a stoichiometry of approximately 2 mol of phosphate/mol of GRK5. The ability of phospholipids to stimulate autophosphorylation is largely blocked by a glutathione S-transferase fusion protein containing the last 102 amino acids of GRK5 (amino acids 489-590), suggesting that this is a primary region involved in GRK5/phospholipid interaction. Phosphoamino acid determination and mutagenesis studies demonstrate that autophosphorylation of GRK5 occurs primarily at residues Ser-484 and Thr-485. Expression and characterization of a mutant GRK5 that does not autophosphorylate (S484A and T485A) reveals that the mutant has a approximately 15-20-fold reduced ability to phosphorylate the beta 2-adrenergic receptor and rhodopsin compared to wild type GRK5. These results suggest that phospholipid-stimulated autophosphorylation may represent a novel mechanism for membrane association and regulation of GRK5 activity.