Targeting the signaling pathway of acylation stimulating protein
Targeting the signaling pathway of acylation stimulating protein
复制标题
DOI：
10.1194/jlr.m500500-jlr200
复制
发表时间：
2006-03-01
影响因子：
6.5
通讯作者：
Cianflone, K
中科院分区：
文献类型：
--
作者：
Maslowska, M;Legakis, H;Cianflone, K
酰化刺激蛋白（ASP；C3adesArg）通过 G 蛋白偶联受体 C5L2 刺激前脂肪细胞/脂肪细胞中的甘油三酯合成 (TGS) 和葡萄糖转运。此处，将 ASP 信号传导与 3T3-L1 细胞中的胰岛素进行比较。 ASP 刺激不是 G alpha(s) 或 G alpha(i) 介导的（百日咳和霍乱毒素不敏感），表明 G(alpha q) 作为候选者。需要磷脂酶 C (PLC)，因为 Ca2+ 螯合剂 1,2-双（邻氨基苯氧基）乙烷-N,N,N',N'-四乙酸四（乙酰氧基甲基）酯和 PLC 抑制剂 U73122 分别使 TGS 的 ASP 刺激降低 93.1% (P < 0.0.001) 和 86.1% (P < 0.004)。 Wortmannin 和 LY294002 分别阻断 ASP 作用 69% (P < 0.001) 和 116.1% (P < 0.003)，支持磷脂酰肌醇 3-激酶 (PI3K) 的参与。 ASP 诱导快速、短暂的 Akt 磷酸化（最大，5 分钟；基础，45 分钟），该磷酸化可被 Akt 抑制所阻断，类似于胰岛素治疗。 PI3K 的下游，哺乳动物雷佩星靶点 (mTOR) 是胰岛素作用所必需的，但 ASP 作用则不需要。相比之下，ASP 和胰岛素均激活丝裂原激活蛋白激酶/细胞外信号调节激酶 (MAPK/ERK1/2) 通路，ERK1/2 磷酸化快速、显着增加，该作用被 PD98059 部分阻断（分别为 64.7% 和 65.9% 抑制；P < 0.001）。通过蛋白质印迹分析证明了时间依赖性（最长 30 分钟）瞬时钙依赖性磷脂酶 A(2) (cPLA2)(-Ser505) 磷酸化（通过 MAPK/ERK1/2）。 ASP 信号传导涉及 PI3K 和 PLC 的顺序激活，以及下游蛋白激酶 C、Akt、MAPK/ERK1/2 和 cPLA2 的激活，所有这些都会导致 TGS 的有效且持久的刺激。
Acylation stimulating protein ( ASP; C3adesArg) stimulates triglyceride synthesis (TGS) and glucose transport in preadipocytes/adipocytes through C5L2,a G-protein-coupled receptor. Here, ASP signaling is compared with insulin in 3T3-L1 cells. ASP stimulation is not G alpha(s) or G alpha(i) mediated ( pertussis and cholera toxin insensitive), suggesting G(alpha q) as a candidate. Phospholipase C ( PLC) is required, because the Ca2+ chelator 1,2-bis(o-aminophenoxy) ethane-N, N, N', N'-tetraacetic acid tetra( acetoxymethyl) ester and the PLC inhibitor U73122 decreased ASP stimulation of TGS by 93.1% (P < 0.0.001) and 86.1% (P < 0.004), respectively. Wortmannin and LY294002 blocked ASP effect by 69% (P < 0.001) and 116.1% (P < 0.003), respectively, supporting phosphatidylinositol 3-kinase (PI3K) involvement. ASP induced rapid, transient Akt phosphorylation ( maximal, 5 min; basal, 45 min), which was blocked by Akt inhibition, resembling treatment by insulin. Downstream of PI3K, mamalian target of rapaycin (mTOR) is required for insulin but not ASP action. By contrast, both ASP and insulin activate the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK1/2) pathway, with rapid, pronounced increases in ERK1/2 phosphorylation, effects partially blocked by PD98059 (64.7% and 65.9% inhibition, respectively; P < 0.001). Time-dependent (maximal, 30 min) transient calcium-dependent phospholipase A(2) (cPLA2)(-Ser505) phosphorylation (by MAPK/ERK1/2) was demonstrated by Western blot analysis. ASP signaling involves sequential activation of PI3K and PLC, with downstream activation of protein kinase C, Akt, MAPK/ERK1/2, and cPLA2, all of which leads to an effective and prolonged stimulation of TGS.