CALPONIN--ITS ROLE IN SMOOTH MUSCLE REGULATION

该子项目的长期目标是解读 钙调蛋白（CaP）在平滑肌收缩调节中的作用。的 CaP的生化特性强烈表明，它可以调节 通过改变肌动蛋白之间的相互作用来增强平滑肌的收缩力 和肌球蛋白。使用外源添加的CaP或CaP的实验结果 反对者似乎支持这一观点。另一方面，在原地 定位研究表明，Cap主要定位于 细胞骨架而不是鸡砂囊细胞的肌动球蛋白区域。 这些发现表明了几种可能性：1）CaP定位于 松弛状态下的肌动球蛋白区域，其功能是抑制 肌动蛋白-肌球蛋白相互作用;刺激后，它迁移出 肌动球蛋白区域到细胞骨架区域。2)CaP不局限于 肌动球蛋白区域与收缩状态和组织类型无关; 相反，它位于细胞骨架区域， 通过细胞骨架的收缩性。3)CaP不参与 收缩性在这个过程中，我们将通过以下方式测试这些可能性： 进行了以下实验：1）原位测定 作为收缩状态和细胞类型的函数的CaP的定位。（二） 测定CaP和各种收缩和收缩因子的体内化学计量， 细胞骨架蛋白3)研究CaP与各种 平滑肌蛋白。4)确定CaP和CaP的影响 拮抗剂对平滑肌细胞收缩性和细胞骨架结构的影响 肌肉细胞该项目的结果可能会揭示出 CaP的生理功能，并揭示平滑肌中的新概念 生理学，如细胞骨架参与收缩性。

The long term objective of this subproject is to decipher the role of calponin (CaP) in the regulation of smooth muscle contraction. The biochemical properties of CaP strongly suggest that it can regulate the contractility of smooth muscle by modifying the interaction between actin and myosin. Results of experiments using exogenously added CaP or CaP antagonist seem to support this notion. On the other hand, in situ localization studies show that Cap is primarily localized in the cytoskeletal rather than the actomyosin regions of chicken gizzard cells. These findings suggest several possibilities: 1) CaP is localized in the actomyosin regions in the relaxed state where it functions by inhibiting actin-myosin interaction; upon stimulation it migrates out of the actomyosin regions to the cytoskeletal regions. 2) CaP is not localized in the actomyosin regions regardless of contractile state and type of tissue; instead, it is localized in the cytoskeletal regions where it modulates contractibility via the cytoskeleton. 3) CaP is not involved in contractibility. In this process we will test these possibilities by carrying out the following experiments: 1) Determine the in situ localization of CaP as a function of contractile state and cell type. 2) Determine the in vivo stoichiometries of CaP and various contractile and cytoskeletal proteins. 3) Study the interaction between CaP and various smooth muscle proteins. 4) Determine the effects of CaP and CaP antagonists on the contractility and cytoskeletal structure of smooth muscle cells. Results derived from this project may reveal the true physiological function of CaP and uncover novel concepts in smooth muscle physiology such as the involvement of the cytoskeleton in contractility.