PROTEIN SER/THR KINASE PRK AND CELL CYCLE PROGRESSION

描述：(改编自调查人员摘要)本提案重点 基于一种新克隆的丝氨酸苏氨酸激酶“PRK”的作用。这 激酶与发芽酵母cdc5和果蝇Polo同源， 此外，它与先前描述的小鼠蛋白激酶有很强的同源性 芬克。PRK最有可能是小鼠FNK的人类同源物。这个 这种激酶的生理作用已经在几个系统中进行了研究 被这些工人。具体地说，已经发现它可以增强黄体酮 反义PrK诱导非洲爪哇卵母细胞减数分裂成熟 转录产物会抑制它们的成熟。它能够拯救一名 酿酒酵母温敏突变株cdc5。它的细胞周期 经过调查发现，监管在S和G2后期达到顶峰 阶段。最有趣的是，它的表达是由血小板生成素激活的 在MO7e巨核细胞和其他巨核细胞系中 与Dami细胞的巨核细胞分化相关。最后，它 已被发现映射到染色体8p21，该区域被认为是 含有肿瘤抑制基因。已经发现，这种情况通常是 与正常组织相比，在肺肿瘤中表达下调。异位 成纤维细胞中的表达降低了生长速度，而且有一些迹象表明 与PRB的互动。拟议研究的目标是：1) 检测PRK是否在调节巨核细胞内丝分裂中起作用 通过异位表达和利用反义和显性抑制进行研究 负突变；2)调查PRK是否发生突变、缺失和/或 自发性肺癌和乳腺癌的失活；3)鉴定蛋白质 通过亲和纯化与PrK相互作用的酵母双杂交 表达文库的系统和体外磷酸化筛选。

DESCRIPTION: (Adapted from investigator's abstract) This proposal focuses upon the role of a newly cloned serine-threonine kinase termed "prk". This kinase is homologous to the budding yeast cdc5 and Drosophila polo and moreover is strongly homologous with the previously described murine kinase fnk. Prk is most likely to be the human homolog of the murine fnk. The physiological role of this kinase has been investigated in several systems by these workers. Specifically, it has been found to enhance progesterone induced meiotic maturation of Xenopus oocytes whereas antisense prk transcripts inhibit their maturation. It is capable of rescuing a thermosensitive cdc5 mutant of Saccharomyces cerevisiae. Its cell cycle regulation has been investigated and found to peak in the late S and G2 phases. Most interestingly, its expression is activated by thrombopoietin in MO7e megakaryocyte cells and other megakaryocytic cell lines and correlated with megakaryocytic differentiation of Dami cells. Finally, it has been found to map to chromosomal locus 8p21, a region proposed to contain tumor suppressor genes. It has been found to be commonly down-regulated in lung tumors compared to normal tissues. Ectopic expression in fibroblasts reduces growth rate and there is some indication of interaction with pRB. The objectives of the proposed studies are: 1) To examine whether prk plays a role in regulating endomitosis in megakaryocytes studied by ectopic expression and by inhibition using antisense and dominant negative mutants; 2) To investigate whether prk is mutated, deleted, and/or inactivated in spontaneous lung and breast cancers; 3) To identify proteins interacting with prk through affinity purification, the yeast two-hybrid system and in vitro phosphorylation screening of an expression library.