Type I collagen structure regulates cell morphology and EGF signaling in primary rat hepatocytes through cAMP-dependent protein kinase A
Type I collagen structure regulates cell morphology and EGF signaling in primary rat hepatocytes through cAMP-dependent protein kinase A
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DOI：
10.1091/mbc.e05-09-0871
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发表时间：
2006-01-01
影响因子：
3.3
通讯作者：
Hansen, LK
中科院分区：
文献类型：
--
作者：
Fassett, J;Tobolt, D;Hansen, LK
与1型胶原的粘附引起不同的反应，这取决于胶原是纤维状（凝胶）还是单体形式（膜）。粘附于胶原膜的肝细胞扩散并增殖，而粘附于胶原凝胶的肝细胞保持圆形并生长停滞。为了探索潜在的细胞内抑制信号的作用，胶原凝胶介导的生长停滞，cAMP依赖性蛋白激酶A（PKA）的肝细胞粘附胶原膜或凝胶进行了检查。在肝细胞周期的G1期，胶原凝胶上的肝细胞PKA活性高于胶片上的肝细胞PKA活性。使用H89抑制PKA增加细胞在胶原凝胶上的铺展，以EGF依赖的方式，而使用8-Br-cAMP激活PKA减少细胞在胶原膜上的铺展。PKA抑制也恢复ERK激活，细胞周期蛋白D1的表达和胶原凝胶上的G1-S进程，但对细胞粘附胶原膜没有影响。EGF受体磷酸化的分析显示，粘附到胶原凝胶改变EGF受体的酪氨酸磷酸化，导致酪氨酸残基845的磷酸化减少，这是通过抑制PKA而增加的。这些结果表明，纤维状1型胶原蛋白可以通过PKA依赖性途径抑制EGF受体的特异性信号，从而积极破坏细胞周期进程。
Adhesion to type 1 collagen elicits different responses dependent on whether the collagen is in fibrillar (gel) or monomeric form (film). Hepatocytes adherent to collagen film spread and proliferate, whereas those adherent to collagen gel remain rounded and growth arrested. To explore the role of potential intracellular inhibitory signals responsible for collagen gel-mediated growth arrest, cAMP-dependent protein kinase A (PKA) was examined in hepatocytes adherent to collagen film or gel. PKA activity was higher in hepatocytes on collagen gel than on film during G1 of the hepatocyte cell cycle. Inhibition of PKA using H89 increased cell spreading on collagen gel in an EGF-dependent manner, whereas activation of PKA using 8-Br-cAMP decreased cell spreading on collagen film. PKA inhibition also restored ERK activation, cyclin D1 expression and G1-S progression on collagen gel, but had no effect on cells adherent to collagen film. Analysis of EGF receptor phosphorylation revealed that adhesion to collagen gel alters tyrosine phosphorylation of the EGF receptor, leading to reduced phosphorylation of tyrosine residue 845, which was increased by inhibition of PKA. These results demonstrate that fibrillar type 1 collagen can actively disrupt cell cycle progression by inhibiting specific signals from the EGF receptor through a PKA-dependent pathway.