Physiological function of acylated proteins in salivary gland

点击翻译按钮获取中文摘要

Recently, the mechanisms for receptor's function and intracellular transmission of various extracellular signals have been gradually clarified and it is no reported that the unique protein (acylated protein; AP) is related to this transmission mechanism. Therefore, in order to define the physiological significance of AP, we tried to analyze not only AP's protein but also its fatty acyl moiety using rat salivary gland as a model cell. The obtained results for the extraction of AP suggest AP that non-ionic detergent, especially Triton X-114, is very valuable using the phase separation method. The composition of fatty acids in membrane-bound proteins from rat parotid gland were analyzed and it was shown that palmitic, myristic and stearic acids were rich in mitochondrial and microsomal membrane fractions. This tendency was stronger in mitochondria than in microsomes. Since the fatty acid composition of membrane proteins was very different from that of membrane phospholipids which was observed previously, the common acyl donors, free fatty acids converted to acyl-CoAs, were analyzed. This fatty acid composition was similar to that of phospholipids and therefore, it is suggested that the enzyme to acylate protein may have very stict specificity for acyl-CoA. in order to clarify the physiological function of AP using salivary gland, it is effective to observe the changes of AP's protein pattern and fatty acyl moiety in the stimulated cells for saliva secretion. although they were analyzed suing phenylephrine and phorbol ester(PMA) for stimuli and radio-labeled fatty acids, the significant alterations in not only membranebound proteins, hoever, but also their fatty acids were not observed under the conditions used. In future, we will experiment to purify AP and clarify its biochemical and physiological characteristics.