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【bio-news】基质刚性和转化生长因子- beta
Cells sense their surroundings not through sight or sound but through the "smell" or "taste" of various soluble factors and the "touch" or "feel" of insoluble mechanical cues. Elasticity of the extracellular matrix (ECM) -- a network of proteins and carbohydrates that surrounds cells -- is one of those mechanical cues, and has been shown to affect the phenotype of a wide range of cells including epithelial cells, neurons, and even stem cells. In a Perspective in the 11 March 2008 issue, R.G. Well and D.E. Discher discussed a recent report demonstrating that the stiffness of the extracellular matrix also influences the release of transforming growth factor-beta, a matrix-bound protein growth factor involved in embryogenesis, malignancy, and fibrosis. The new work shows that that a soft ECM deforms under the stresses applied by cells, leaving the protein complex that contains TGF-beta intact, and the growth factor sequestered in the matrix. A stiff matrix however, resists deformation and releases TGF-beta so it can bind cell-surface receptors and promote cellular differentiation and proliferation. The findings suggest that mechanics-driven mechanisms may regulate the equilibrium between storage and release of other matrix-bound growth factors as well. 细胞对其周边的感觉不是通过视或听，而是通过对各种可溶性因子的“嗅”或“品尝”以及对非溶性的机械性信号的“触”或“摸”。细胞外基质（ECM）的弹性（所谓细胞外基质是细胞周围的蛋白质及碳水化合物网状结构）就是这些机械性信号之一，而这些机械性信号已被发现会影响广范围细胞的表现型，其中包括上皮细胞、神经元甚至还有干细胞。在2008年3月11日刊的Perspective< http://stke.sciencemag.org/cgi/content/short/1/10/pe13 > 上，
R.G. Well和 D.E. Discher对一则最近的报告进行了讨论，该报告证明了细胞外基质的刚性还会影响转化生长因子-beta的释放，而转化生长因子-beta是一种与胚胎发生、恶性肿瘤及纤维化有关的与基质结合的蛋白生长因子。这一新的研究工作显示，软性ECM在细胞施加的压力下会变形，使得含有TGF-beta的蛋白复合物维持完整状态并使生长因子被封存在基质之中。然而，刚性的基质会抗拒这一变形并释放TGF-beta, 使其能够与细胞表面的受体结合并促进细胞分化和增生。这些发现表明，力学驱动的机制也可以调节其他与基质结合的生长因子的储存与释放之间的平衡。
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作者:admin@医学,生命科学 2010-11-08 17:11
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