AMP-activated protein kinase β subunit tethers α and γ Subunits via its C-terminal sequence (186-270)
AMP-activated protein kinase β subunit tethers α and γ Subunits via its C-terminal sequence (186-270)
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DOI：
10.1074/jbc.m412993200
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发表时间：
2005-04-08
影响因子：
4.8
通讯作者：
Stapleton, D
中科院分区：
文献类型：
--
作者：
Iseli, TJ;Walter, M;Stapleton, D
DAMP激活的蛋白激酶(AMPK)是一种重要的代谢应激敏感蛋白激酶，负责调节新陈代谢，以应对不断变化的能量需求和营养供应。哺乳动物AMPK是一种稳定的α-β-γ杂三聚体，由一个催化α和两个非催化亚基--β和伽马组成。β亚基通过N-末端肉豆蔻基向膜靶向AMPK，通过中分子糖原结合域靶向糖原。在这里，我们发现β亚基的保守的C-末端85-残基序列，β1-(186-270)，足以形成活性依赖于AMP的异三聚体α1-β1-(186-270)-伽马1，而25个残基的β1 C-末端(246 270)序列足以结合伽马1，伽马2或伽马3，但不能结合α亚基。缺失β-C末端的Ile-270可在没有α亚基的情况下排除β-γ结合，但α亚基的存在或用Ala或Glu替代Ile-270可恢复β-伽马结合。截短α亚基表明，β1结合需要α1-(313-473)序列。β亚基的保守的C-末端85个残基序列(在β1和β2之间占90%)是负责形成AMPKαβγ杂三聚体的主要α-伽马结合序列。
dAMP-activated protein kinase (AMPK) is an important metabolic stress-sensing protein kinase responsible for regulating metabolism in response to changing energy demand and nutrient supply. Mammalian AMPK is a stable alpha beta gamma heterotrimer comprising a catalytic alpha and two non-catalytic subunits, beta and gamma. The beta subunit targets AMPK to membranes via an N-terminal myristoyl group and to glycogen via a mid-molecule glycogen-binding domain. Here we find that the conserved C-terminal 85-residue sequence of the beta subunit, beta 1-(186-270), is sufficient to form an active AMP-dependent heterotrimer alpha 1 beta 1-(186-270)-gamma 1, whereas the 25-residue beta 1 C-terminal (246 270) sequence is sufficient to bind gamma 1, gamma 2, or gamma 3 but not the alpha subunit. Deletion of the beta C-terminal Ile-270 precludes beta gamma association in the absence of the alpha subunit, but the presence of the alpha subunit or substitution of Ile-270 with Ala or Glu restores beta gamma binding. Truncation of the alpha subunit reveals that beta 1 binding requires the alpha 1-(313-473) sequence. The conserved C-terminal 85-residue sequence of the beta subunit (90% between beta 1 and beta 2) is the primary alpha gamma binding sequence responsible for the formation of the AMPK alpha beta gamma heterotrimer.