FUNCTION AND REGULATION OF INTERCELLULAR COMMUNICATION

缝隙连接介导的细胞间通讯被认为是 是关键的细胞行为的基础，例如电信号的传播 平滑肌和心肌的兴奋性。然而，缝隙连接也 选择性地连接许多非兴奋性组织中的细胞。在这些情况下， 交流的生物学意义尚不清楚。一种新的方法 要定义非兴奋性细胞之间的通信的作用将是 使用：我们已经创造了连接蛋白突变，其功能是显性的- 消极的沟通抑制因素。这些突变体，不会形成 激活的通道，可以与正常的连接蛋白相互作用并抑制其 形成活跃渠道的能力。分析……的重要性 胚胎发生、器官动态平衡/生理学与肿瘤的沟通 抑制，我们将在非洲爪哇早期表达抑制连接蛋白突变体 在啮齿类动物的发育、乳腺形态发生和哺乳期。 我们发现一种人类遗传性疾病，X连锁夏科特- Marie-Tooth病(CMTX)与基因突变有关 编码连接蛋白32。CMTX是一种脱髓鞘周围神经病。我们 已经证明Cx32在雪旺细胞中含量丰富，这与 这种疾病的表现。然而，目前尚不清楚CMTX如何 突变影响Cx32通道的活性，也不影响Cx32的活性，或者 其他可能存在的连接蛋白会影响髓鞘形成。去调查 这些问题，我们将使用配对的卵母细胞系统来测试确定的Cx32 为了活跃性的突变。其他连接蛋白的细胞位置可能 将被确定是否存在于雪旺细胞中。一个动物模型将会是 开发的目的是为了研究这种疾病的早期阶段。 缝隙连接通道可以被pH、Ca++、跨结电压门控 而且，正如我们最近所展示的，通过磷酸化。V-src诱导的酪氨酸 Cx43的磷酸化深刻抑制细胞间的活性 包含它的通道，与通信中的角色一致 通过v-src进行变换。我们建议测试a)其他连接蛋白是否可以 以这种方式调节b)如果v-src以外的激酶可以施加 C)如果Cx43的门控在体内没有 V-源。后者将通过产生一种特异性抗体来进行评估 Cx43在酪氨酸-265位发生磷酸化。

Intercellular communication mediated by gap junctions is believed to underlie crucial cell behaviors such as the spread of electrical excitation in smooth and cardiac muscle. However, gap junctions also selectively connect cells in many non-excitable tissues. In these cases, the biological significance of communication is not clear. A novel method to define the role of communication between nonexcitable cells will be used: We have created connexin mutations that function as dominant- negative inhibitors of communication. These mutants, which do not form active channels, can interact with normal connexins and suppress their ability to form active channels. To analyze the importance of communication in embryogenesis, organ homeostasis/physiology and tumor suppression, we will express inhibiting connexin mutants in early Xenopus development and during rodent mammary gland morphogenesis and lactation. We have discovered that a human hereditary disorder, X-linked Charcot- Marie-Tooth disease (CMTX), is associated with mutations in the gene encoding connexin32. CMTX is a demyelinating peripheral neuropathy. We have shown that Cx32 is abundant in Schwann cells which is consistent with the presentation of this disease. However, it is not known how the CMTX mutations affect Cx32 channel activity, nor how the activity of Cx32, or other connexins that may be present, influence myelination. To investigate these issues, we will use the paired oocyte system to test identified Cx32 mutations for activity. The cellular location of other connexins that may be present in Schwann cells will be determined. An animal model will be developed to permit the early phases of this disease to be studied. Gap junction channels can be gated by pH, Ca++, transjunctional voltage and, as we have recently shown, by phosphorylation. V-src induced tyrosine phosphorylation of Cx43 profoundly inhibits the activity intercellular channels containing it, consistent with a role for communication in transformation by v-src. We propose to test a) if other connexins can be regulated in this fashion b) if kinases other than v-src can exert a similar effect and c) if gating of Cx43 occurs in vivo in the absence of v-src. The latter will be assessed by producing an antibody specific for Cx43 phophorylated at tyrosine-265.