Overview:
GRK7 is a member of the G protein-coupled receptor kinase subfamily and is a Ser/Thr protein kinase. GRK7 is specifically expressed in the retina and has been shown to phosphorylate cone opsins and initiate their deactivation (1). GRK7 catalyzes rhodopsin phosphorylation in a light-dependent manner. GRK7 co-localizes with GRK1 in human cone outer segments. PKA phosphorylates GRK7 at Ser(23) and Ser(36) in vitro andphosphorylation of GRK7 by PKA reduces the ability of GRK7 to phosphorylate rhodopsin in vitro (2). Since exposure to light causes a decrease in cAMP levels in rod cells, it is proposed that phosphorylation of GRK7 by PKA occurs in the dark.
Gene Aliases:
GPRK7
Genbank Number:
NM_139209
References:
1. Chen, C-K. et al: Characterization of human GRK7 as a potential cone opsin kinase. Molec. Vision 7: 305-313, 2001. 2. Horner, T J. et al: Phosphorylation of GRK1 and GRK7 by cAMP-dependent protein kinase attenuates their enzymatic activities. J Biol Chem. 2005 Aug 5;280(31):28241-50.
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没有序列识别的功能,他就是简单的催化相邻DNA链的5-P末端和3'-OH末端以磷酸二酯键结合的反应,需ATP作辅酶。 不仅可以催化粘性末端之间或平滑末端之间的DNA的连接,也催化DNA与RNA之间以及少数RNA之间的连接。
反转录酶(Reversetranscripatase)是以RNA为模板指导三磷酸脱氧核苷酸合成互补DNA(cDNA)的酶。哺乳类C型病毒的反转录酶和鼠类B型病毒的反转录酶都是一条多肽链。鸟类RNA病毒的反转录酶则由两上亚基结构。真核生物中也都分离出具有不同结构的反转录酶。
TERT是端粒酶逆转录酶
人的端粒酶是由端粒酶逆转录酶、端粒酶RNA和一种假尿嘧啶合成酶组成

