Liu P, Ying Y, Anderson R G
Department of Cell Biology and Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75235-9039, USA.
Proc Natl Acad Sci U S A. 1997 Dec 9;94(25):13666-70. doi: 10.1073/pnas.94.25.13666.
The ability of a peptide hormone to affect many different intracellular targets is thought to be possible because of the modular organization of signal transducing molecules in the cell. Evidence for the presence of signaling modules in metazoan cells, however, is incomplete. Herein we show, with morphology and cell fractionation, that all the components of a mitogen-activated protein kinase pathway are concentrated in caveolae of unstimulated human fibroblasts. Addition of platelet-derived growth factor to either the intact cell or caveolae isolated from these cells stimulates tyrosine phosphorylation and activates mitogen-activated protein kinases in caveolae. The molecular machinery for kinase activation, therefore, is preorganized at the cell surface of quiescent cells.
一种肽激素能够影响许多不同的细胞内靶点，这被认为是可能的，因为细胞中信号转导分子的模块化组织。然而，后生动物细胞中信号模块存在的证据并不完整。在此，我们通过形态学和细胞分级分离表明，丝裂原活化蛋白激酶途径的所有组分都集中在未受刺激的人成纤维细胞的小窝中。向完整细胞或从这些细胞分离的小窝中添加血小板衍生生长因子会刺激酪氨酸磷酸化并激活小窝中的丝裂原活化蛋白激酶。因此，激酶激活的分子机制在静止细胞的细胞表面预先组织好了。
