Binding of myristoylated alanine-rich protein kinase C substrate to phosphoinositides attenuates the phosphorylation by protein kinase C.
Binding of myristoylated alanine-rich protein kinase C substrate to phosphoinositides attenuates the phosphorylation by protein kinase C.
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肉豆蔻酰化富含丙氨酸的蛋白激酶 C 底物与磷酸肌醇的结合减弱了蛋白激酶 C 的磷酸化。
DOI：
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发表时间：
1996
影响因子：
3.9
通讯作者：
K. Huang
中科院分区：
文献类型：
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作者：
K. Seki;F. Sheu;K. Huang
豆蔻酰化富丙氨酸蛋白激酶C底物（MARCKS）是一种外周膜蛋白，在膜和胞质溶胶之间进行磷酸化依赖性易位。MARCKS以高亲和力（Kd小于0.5 μ M）与酸性磷脂结合，但与中性磷脂结合较差。虽然MARCKS与酸性磷脂的相互作用缺乏特异性，当通过结合试验测定时，这些磷脂对蛋白激酶C（PKC）对该蛋白的磷酸化产生独特的影响。用磷脂酰丝氨酸（PS）或磷脂酰甘油预孵育MARCKS增强磷酸化;而用磷脂酸、磷脂酰肌醇（PI）、磷脂酰肌醇-4-磷酸或磷脂酰肌醇-4，5-二磷酸抑制PKC对该底物的磷酸化。磷酸肌醇抑制MARCKS磷酸化显然是针对在基板，而不是在激酶的磷酸化的其他两个磷脂结合PKC底物，神经调节蛋白和神经颗粒蛋白，表现出不同的反应，从那些MARCKS。此外，磷酸肌醇对MARCKS磷酸化的抑制作用见于PKC同工酶α、β、γ和δ以及PKC的催化片段蛋白激酶M。一个25个氨基酸的合成肽对应的磷酸化位点结构域（PSD）的MARCKS，但不是豆蔻酰化的N-末端肽，竞争同样有效地与MARCKS在结合到PS或PI-含有囊泡，这表明这两个磷脂结合到PSD的MARCKS。PI与MARCKS的结合抑制了所有三个磷酸化位点的PKC磷酸化。这些结果表明，磷脂酰肌醇和PS结合在不同的残基内的MARCKS PSD，使所得的磷脂/MARCKS复合物被PKC差异磷酸化。
The myristoylated aline-rich protein kinase C substrate (MARCKS) is a peripheral membrane protein that undergoes phosphorylation-dependent translocation between membrane and cytosol. MARCKS binds to acidic phospholipids with high affinity (Kd less than 0.5 microM) but binds poorly to neutral phospholipids. Although interaction of MARCKS with acidic phospholipids lacks specificity when determined by binding assay, these phospholipids exert distinctive effects on the phosphorylation of this protein by protein kinase C (PKC). Preincubation of MARCKS with phosphatidylserine (PS) or phosphatidylglycerol enhanced the phosphorylation; whereas with phosphatidic acid, phosphatidylinositol (PI), phosphatidylinositol-4-phosphate, or phosphatidylinositol-4,5-biphosphate inhibited the phosphorylation of this substrate by PKC. Phosphoinositide inhibition of MARCKS phosphorylation was apparently directed at the substrate rather than at the kinase as the phosphorylation of two other phospholipid-binding PKC substrates, neuromodulin and neurogranin, exhibited different responses from those of MARCKS. Furthermore, the inhibition of phosphoinositides on MARCKS phosphorylation was seen with PKC isozymes alpha, beta, gamma, and delta and with the catalytic fragment of PKC, protein kinase M. A 25-amino-acid synthetic peptide corresponding to the phosphorylation site domain (PSD) of MARCKS, but not to the myristoylated N-terminal peptide, competed equally effectively with MARCKS in binding to either PS- or PI-containing vesicles, suggesting that both phospholipids bind to the PSD of MARCKS. Binding of PI to MARCKS inhibited PKC phosphorylation of all three phosphorylation sites. These results suggest that phosphoinositides and PS bind at different residues within the MARCKS PSD, so that the resulting phospholipid/MARCKS complexes are differentially phosphorylated by PKC.