Phosphorylation sites within alpha4 subunits of alpha4beta2 neuronal nicotinic receptors: a comparison of substrate specificities for cAMP-dependent protein kinase (PKA) and protein kinase C (PKC).
Phosphorylation sites within alpha4 subunits of alpha4beta2 neuronal nicotinic receptors: a comparison of substrate specificities for cAMP-dependent protein kinase (PKA) and protein kinase C (PKC).
复制标题
α4β2 神经元烟碱受体的 α4 亚基内的磷酸化位点：cAMP 依赖性蛋白激酶 (PKA) 和蛋白激酶 C (PKC) 底物特异性的比较。
DOI：
10.1023/a:1022892400362
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发表时间：
2003
影响因子：
4.4
通讯作者：
Rogers,ChristopherQ
中科院分区：
文献类型：
--
作者：
Wecker,Lynn;Rogers,ChristopherQ
The present study determined whether putative phosphorylation sites within the M3/M4 cytoplasmic domain of the human α4 subunit of α4β2 neuronal nicotinic receptors are substrates for cAMP-dependent protein kinase (PKA) or protein kinase C (PKC). Five peptides corresponding to predicted phosphorylation sequences were synthesized, and phosphorylation was compared with standard peptide substrates for each kinase, that is, Kemptide for PKA and glycogen synthase (GS) 1-8 for PKC. VRCRSRSI had the highest affinity for PKA, with a Km of 44.5 μM; Kemptide had a Km of 7.7 μM. LMKRPSVVK and KARSLSVQH were also phosphorylated by PKA, but had lower affinities of 593 μM and 2896 μM, respectively. LMKRPSVVK had the highest affinity for PKC with a Km of 182 μM; GS 1–8 had a Km of 2.1 μM. VRCRSRSI had a comparative affinity for PKC with a Km of 327 μM. PCKCTCKK was not phosphorylated by PKA, but was a substrate for PKC with a Km of 1392 μM, whereas PGPSCKSP was not phosphorylated by either kinase. Based on these findings, results suggest that Ser-362 and Ser-486 on the human α4 subunit may be phosphorylated by either PKA or PKC, Ser-467 is a putative PKA site, and Thr-532 represents a likely PKC substrate; Ser-421 does not appear to be phosphorylated by either kinase.
