STUDIES ON THE NATURE AND FUNCTION OF THE PHOSPHOPROTEIN, PROSOLIN

对独特的18.4K，pI 5.9磷蛋白的研究仍在继续， 前溶胶蛋白（以前称为pp 17）是一种主要的胞质蛋白， 在HL 60早幼粒细胞白血病中经历快速磷酸化 当它们的生长被抑制时，它们被诱导 分化响应佛波醇酯（TPA）的治疗。 人外周血淋巴细胞原溶胶蛋白的表达及磷酸化 淋巴细胞（PBL）。 Prosolin被鉴定为 PBL中，其表达与S期相关 细胞周期。 在增殖的PBL中，前溶胶蛋白是主要的调节因子。 胞质组分，占总胞质蛋白的0.5%， 其中25%为2种磷酸化形式。 TPA治疗 增殖的PBL引起约2/3的前 在1小时内存在未磷酸化的前溶胶蛋白， DNA合成突然停止。 磷酸化 前溶胶蛋白可能是抗增殖性肿瘤的起始事件。 对TPA的回应 只有在S期才能使用prosolin 可以提供一种调节机制， 细胞因子可通过激活 与前溶胶蛋白磷酸化有关的抗增殖过程 而不抑制Go或G1细胞的活化。

Studies have continued on the unique 18.4K, pI 5.9 phosphoprotein, prosolin (formerly called pp17), a major cytosolic protein which undergoes rapid phosphorylation in HL60 promyelocytic leukemia cells when their growth is inhibited and they are induced to differentiate in response to treatment with phorbol ester (TPA). The expression and phosphorylation of prosolin in human peripheral lymphocytes (PBL) was investigated. Prosolin was identified in PBL, and its expression was found to be correlated with the S-phase of the cell cycle. In proliferating PBL prosolin was a major cytosolic component, comprising 0.5% of total cytosolic protein, of which 25% was found in 2 phosphorylated forms. TPA treatment of proliferating PBL caused phosphorylation of about 2/3 of pre- existing unphosphorylated prosolin within 1 hr followed immediately by an abrupt cessation of DNA synthesis. Phosphorylation of prosolin may be an initiating event in the antiproliferative response to TPA. The availability of prosolin only during S-phase may provide a regulatory mechanism by which naturally occuring cytokines may terminate lymphocyte growth, through activiation of antiproliferative processes linked to phosphorylation of prosolin without inhibiting activation of Go or G1 cells.