Cytoskeletal proteins working in the process of secretion

1.肾上腺髓质细胞骨架蛋白的特性从肾上腺髓质膜组分中发现并纯化了一种新的肌动蛋白结合蛋白。该蛋白被认为是G蛋白，因为该蛋白是用不可水解的GTP类似物S从膜组分中溶解出来的。然而，使用针对已知G蛋白的抗体(如Gi、Go和Gs)进行的免疫印迹实验表明，该蛋白不与该蛋白反应，并且针对该蛋白制备的抗体也不与这些G蛋白反应。对这种蛋白质的结构分析目前正在进行中。中枢神经系统膜蛋白的分析。提纯了一种富含脑组织膜部分的具有钙调素结合活性的新蛋白，并通过克隆确定了其分子结构。该蛋白是一种酸性蛋白，具有独特的氨基酸组成，几乎不含疏水残基，并对热和酸处理表现出抗性。这些特征与Marcks和GAP-43的特征相似。在它的N端，这个蛋白质有一个麦芽糖基化位点，这种脂质的加入被认为是它移位到细胞膜上的原因。使用特异性抗体的研究表明，它在神经组织中的特异性表达，它的发育变化的表达，以及它在神经元膜上的定位。

1. Characterization of the cytoskeletal proteins of adrenal medulla. A new actin binding protein was found and purified from the membrane fraction of adrenal medulla. This protein was assumed to be a G-protein, for this protein was solubilized from the membrane fraction using GTP S, a nonhydrolyzable GTP analogue. Immunoblotting experiments using antibodies against known G proteins, such as Gi, Go, and Gs, however, showed no reactivity with this protein and antibody prepared against this protein showed also no reactivity with these G-proteins. A structural analysis of this protein is now under progress.2. Analysis of membrane proteins of the central nervous system. A new protein, rich in the membrane fraction of brain tissue and having a calmodulin binding activity, was purified and its molecular structure was clarified by cDNA cloning. This protein was an acidic protein having a unique amino acids composition containing few hydrophobic residues and showed resistance to heat and acid treatments. These characters resemble to these of MARCKS and GAP-43. In its N-terminal end, this protein has a myrystoylation site and the addition of this lipid is thought to be responsible to its translocation to the cell membrane. Studies using specific antibody showed its specific expression in the nervous tissue, its developmentally changed expression and its localization in the membrane of the neuron.