PKC-DELTA IN HEMATOPOIETIC CELL DIFFERENTIATION PATHWAY

蛋白激酶C(PKC)在细胞生长和生长中起着非常重要的作用 差异化。最近的研究表明，在几个PKC中 已研究同种异构体。只有PKC-α和PKC-Delta能够诱导 32D细胞过度表达时的单核细胞分化 细胞，并被12-0-十四酰佛波醇-i3-乙酸酯(TPA)激活。在……里面 为了阐明PKC-α和PKC-Delta的可能机制。 诱导单核细胞分化。分析TPA刺激是否 导致细胞底物(S)酪氨酸磷酸化 对32D/PKC-α和32D/PKC-Delta转染体进行了研究。结果 证明PKC-Delta本身是酪氨酸磷酸化的 对TPA刺激的反应。PKC-Delta的酪氨酸磷酸化是 在TPA诱导32D/PKC-Delta细胞分化的整个过程中观察 句号。当杆状病毒衍生的PKC-Delta 与血小板衍生生长因子(PDGF)-β-R体外孵育。 胰岛素受体或非受体酪氨酸激酶，Fyn。PKC-Delta 体外酪氨酸磷酸化后活性增加 它的底物。PKC-Delta和PDGF-β-R在32D细胞中的共转染 (32D/PDGF-beta-R/PKC-Delta)提供了PKC-Delta是 从细胞质转移到细胞膜。和酪氨酸 当细胞受到PDGF刺激时，膜上的磷酸化- BB。膜组分中PKC-Delta活性也升高。 提示PKC-Delta酪氨酸之间呈正相关 磷酸化及其在体内的激活。32D/PDGF-β-R/PKC-Delta 细胞在PDGF-BB作用下向巨噬细胞分化 一夜之间。而PDGF-BB对转导PDGF-BB的32D细胞的作用 单独的β-R导致了非常轻微的分化。这些结果 提示PKC-Delta在髓系中起着非常重要的作用 当它被TPA或重组的PDGF激活时- β-R信号通路。

Protein kinase C (PKC) plays a very important role in cell growth and differentiation. Recent work has demonstrated that among several PKC isoforms investigated. only PKC-alpha and PKC-delta were able to induce 32D cell monocytic differentiation when they were overexpressed in 32D cells and activated by 12-0-tetradecanoyl-phorbol-I3-acetat (TPA). In order to elucidate the possible mechanism of PKC-alpha- and PKC-delta- induced monocytic differentiation. analysis of whether TPA stimulation resulted in tyrosine phosphorylation of cellular substrate(s) in the 32D/PKC-alpha and 32D/PKC-delta transfectants was investigated. Results demonstrated that PKC-delta itself was tyrosine phosphorylated in response to TPA stimulation. Tyrosine phosphorylation of PKC-delta was observed during the entire TPA-induced 32D/PKC-delta cell differentiation period. It also occurred when baculovirus-derived PKC-delta was incubated in vitro with platelet-derived growth factor (PDGF)-beta-R. insulin receptor or a nonreceptor tyrosine kinase, fyn. PKC-delta activity after tyrosine phosphorylation in vitro was increased towards its substrate. Cotransfection of PKC-delta and PDGF-beta-R in 32D cells (32D/PDGF-beta-R/PKC-delta) provided evidence that PKC-delta was translocated from the cytosol to the membrane. and tyrosine phosphorylated in the membrane when the cells were stimulated with PDGF- BB. PKC-delta activity was also increased in the membrane fraction. indicating the positive correlation between PKC-delta tyrosine phosphorylation and its activation in vivo. 32D/PDGF-beta-R/PKC-delta cells differentiated toward macrophages when they were exposed to PDGF-BB overnight. whereas PDGF-BB treatment of 32D cells transfected with PDGF- beta-R alone resulted in very slight differentiation. These results suggest that PKC-delta plays a very important role in myeloid differentiatiOn when it is activated by TPA or by a reconstituted PDGF- beta-R signaling pathway.