Parent C A, Blacklock B J, Froehlich W M, Murphy D B, Devreotes P N
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Cell. 1998 Oct 2;95(1):81-91. doi: 10.1016/s0092-8674(00)81784-5.
Directional sensing by eukaryotic cells does not require polarization of chemoattractant receptors. The translocation of the PH domain-containing protein CRAC in D. discoideum to binding sites on the inner face of the plasma membrane reflects activation of the G protein-linked signaling system. Increments in chemoattractant elicit a uniform response around the cell periphery. Yet when cells are exposed to a gradient, the activation occurs selectively at the stimulated edge, even in immobilized cells. We propose that such localized activation, transmitted by the recruitment of cytosolic proteins, may be a general mechanism for gradient sensing by G protein-linked chemotactic systems including those involving chemotactic cytokines in leukocytes.
真核细胞的定向感知并不需要趋化因子受体的极化。盘基网柄菌中含PH结构域的蛋白CRAC向质膜内表面结合位点的转位反映了G蛋白偶联信号系统的激活。趋化因子的增加会在细胞周边引发均匀的反应。然而，当细胞暴露于梯度环境中时，即使是固定化的细胞，激活也会选择性地发生在受刺激的边缘。我们提出，这种通过招募胞质蛋白传递的局部激活可能是G蛋白偶联趋化系统（包括那些涉及白细胞趋化细胞因子的系统）感知梯度的一般机制。
