CONTROL OF CALCIUM AND PHOSPHORYLATION-REGULATED SIGNALLING PATHWAYS

分子研究被用来确定钙调蛋白的作用 淋巴因子基因中钙调神经磷酸酶(CaM)依赖的蛋白磷酸酶(CN) 免疫抑制剂环孢素A的激活及其敏感性 和FK-506。使用在细菌中表达的缺失突变体，最低限度 显示了催化(A)亚基上约40个残基的结构域 对于结合调节的(B)亚单位是必要和充分的。 这些突变体在人T细胞中的表达表明，A：B二聚体 需要复合体来激活白细胞介素2启动子并赋予 免疫抑制耐药。值得注意的是，粗毛拟青霉的转基因 亚基产生与哺乳动物CN-A相同的效应，即， 激活多种转录元件(核因子-AT、核因子-KB、OAP)和 内源性哺乳动物与药物依赖复合体的形成 免疫亲和素。因此，真菌和哺乳动物的酶都是保守的。 独特的催化专一性和免疫亲和性识别；这可能 暗示了免疫亲和素调节的生物学需要，可能是通过 天然生成的配体。CN对反式作用的多效性效应 影响IL-2诱导的因素提示它们的激活是 间接的，可能发生在这些组件的上游。在……里面 小鼠脑内的原位杂交和免疫定位研究表明 钙调素依赖的磷酸二酯酶的限制性表达模式 (PDE)亚型，PDE1B1，与神经元中的重要作用一致 含有D1多巴胺能受体。与PDE1A2亚型相反， PDE1B1似乎不与CaM敏感的腺苷共定位 环化酶，提示这两种酶参与不同的时间 对刺激反应的循环AMP降解模式。一种潜力 磷脂酰肌醇特异性磷脂酶C酶的同源性 在细菌和布氏毛滴虫中描述。使用基于PCR的方法，CAPP-36 从牛、鼠和人来源获得cDNA，并表达 研究表明，这种异构体的信使核糖核酸在小脑中丰富。 未来的研究将检查这种蛋白质的生物活性 它在哺乳动物细胞中的过度表达。

Molecular studies were conducted to define the role of the calmodulin (CaM)-dependent protein phosphatase, calcineurin (CN), in lymphokine gene activation and its sensitivity to the immunosuppressants, Cyclosporin A and FK-506. Using deletion mutants expressed in bacteria, a minimal domain of approximately 40 residues on the catalytic (A) subunit was shown to be necessary and sufficient for binding the regulatory (B) subunit. Expression of these mutants in human T cells showed that the dimeric A:B complex is needed to activate the interleukin (IL-2 promoter and to confer immunosuppressant resistance. Remarkably, transfection of N. crassa A subunit produces the same effects seen with mammalian CN-A, i.e., activation of multiple transcriptional elements (NF-AT, NF-KB, OAP) and formation of drug-dependent complexes with endogenous mammalian immunophilins. Thus, the fungal and mammalian enzymes have conserved both a distinctive catalytic specificity and immunophilin recognition; this may imply a biological need for regulation by immunophilins, perhaps via naturally occurring ligands. The pleiotropic effect of CN on trans-acting factors affecting IL-2 induction suggests that their activation is indirect, probably occurring at a site upstream of these components. In situ hybridization and immunolocalization studies in mouse brain showed a restricted pattern of expression for the CaM-dependent phosphodiesterase (PDE) isoform, PDE1B1, consistent with an important role in neurons containing D1 dopaminergic receptors. In contrast to the PDE1A2 isoform, it appears the PDE1B1 does not co-localize with CaM-sensitive adenylate cyclase, suggesting that the two enzymes participate in different temporal patterns of cyclic AMP degradation in response to stimuli. A potential homolog of phosphatidyl-inositol specific phospholipase C enzymes described in bacteria and T. brucei. Using PCR-based methods, CAPP-36 CDNAS were obtained from bovine, murine and human sources, and expression studies indicate that MRNA for this isoform is enriched in the cerebellum. Future studies will examine the biological activity of this protein after its overexpression in mammalian cells.