DISSOCIATION OF PHOSPHORYLATION AND TRANSLOCATION OF A MYRISTOYLATED PROTEIN-KINASE-C SUBSTRATE (MARCKS PROTEIN) IN C6 GLIOMA AND N1E-115 NEUROBLASTOMA-CELLS
DISSOCIATION OF PHOSPHORYLATION AND TRANSLOCATION OF A MYRISTOYLATED PROTEIN-KINASE-C SUBSTRATE (MARCKS PROTEIN) IN C6 GLIOMA AND N1E-115 NEUROBLASTOMA-CELLS
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DOI：
10.1111/j.1471-4159.1993.tb03303.x
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发表时间：
1993-04-01
影响因子：
4.7
通讯作者：
COOK, HW
中科院分区：
文献类型：
--
作者：
BYERS, DM;PALMER, FBSC;COOK, HW
C6 神经胶质瘤和 N1E-115 神经母细胞瘤细胞中标记有 [H-3] 肉豆蔻酸的 80 kDa 蛋白因其钙调蛋白结合性、酸性、热稳定性和免疫化学特性而被鉴定为肉豆蔻酰化富含丙氨酸的 C 激酶底物（MARCKS 蛋白）。当用 [H-3] 肉豆蔻酸酯预孵育的 C6 细胞用 200 nM 4β-12-O-十四烷酰佛波醇 13-乙酸酯 (β-TPA) 处理时，可溶性洋地黄皂苷组分中标记的 MARCKS 迅速增加（最大，10 分钟时增加五倍），同时 Triton X-100 可溶性膜组分减少。然而，在存在 β-TPA 的情况下，两种级分中该蛋白质的磷酸化程度均相似（最大，30 分钟时增加四倍）。相反，N1E-115细胞中β-TPA刺激的MARCKS磷酸化仅限于膜部分，并且相对于α-TPA对照，肉豆蔻酰化蛋白的分布没有变化。这些结果表明，尽管蛋白激酶 C 对 MARCKS 的磷酸化发生在两种细胞系中，但它与从膜到胞浆的易位没有直接关系，而这种易位仅发生在 C6 细胞中。 MARCKS 的细胞特异性易位似乎与先前证明的佛波酯对刺激这两种细胞系中磷脂酰胆碱周转的差异效应相关。
An 80-kDa protein labeled with [H-3]myristic acid in C6 glioma and N1E-115 neuroblastoma cells has been identified as the myristoylated alanine-rich C kinase substrate (MARCKS protein) on the basis of its calmodulin-binding, acidic nature, heat stability, and immunochemical properties. When C6 cells preincubated with [H-3]myristate were treated with 200 nM 4beta-12-O-tetradecanoylphorbol 13-acetate (beta-TPA), labeled MARCKS was rapidly increased in the soluble digitonin fraction (maximal, fivefold at 10 min) with a concomitant decrease in the Triton X-100-soluble membrane fraction. However, phosphorylation of this protein was increased, in the presence of beta-TPA to a similar extent in both fractions (maximal, fourfold at 30 min). In contrast, beta-TPA-stimulated phosphorylation of MARCKS in N1E-115 cells was confined to the membrane fraction only and no change in the distribution of the myristoylated protein was noted relative to alpha-TPA controls. These results indicate that although phosphorylation of MARCKS by protein kinase C occurs in both cell lines, it is not directly associated with translocation from membrane to cytosol, which occurs in C6 cells only. The cell-specific translocation of MARCKS appears to correlate with previously demonstrated differential effects of phorbol esters on stimulation of phosphatidylcholine turnover in these two cell lines.