Oviedo-Orta Ernesto, Evans W Howard
Bristol Heart Institute, Bristol Royal Infirmary, United Kingdom.
J Leukoc Biol. 2002 Oct;72(4):636-42.
Gap junctional communication is a widespread mechanism for metabolic coupling of adjoining cells. In the immune system, evidence has built up showing that lymphocytes possess the protein building blocks of gap junctions, the connexins. The most widespread is connexin 43, but connexin 40 is also present in secondary lymphoid organs. Inhibitors of gap junctional communication, especially the highly specific connexin mimetic peptides, have been shown to decrease the secretion of immunoglobulins and cytokines by T and B lymphocyte cocultures, indicating that connexins may play a fundamental role in lymphocyte physiology. Traditionally, connexins function when assembled into gap junction-intercellular channels. However, the possibility is now arising that gap junction hemichannels, previously viewed as plasma membrane precursors of gap junctions, are also involved in the release from cells of small metabolites, e.g., adenosine 5'-triphosphate and nicotinamide adenine dinucleotide(+), and this opens up a second, possible paracrine function for connexins detected in lymphocytes. The increasing structural and functional evidence points to a potential role that lymphocyte gap junctional intercellular communication may play within the complex signaling components of the immunological synapse.
间隙连接通讯是相邻细胞代谢偶联的一种广泛存在的机制。在免疫系统中，越来越多的证据表明淋巴细胞拥有间隙连接的蛋白质组成成分——连接蛋白。分布最广泛的是连接蛋白43，但连接蛋白40也存在于次级淋巴器官中。间隙连接通讯的抑制剂，尤其是高度特异性的连接蛋白模拟肽，已被证明可减少T和B淋巴细胞共培养物中免疫球蛋白和细胞因子的分泌，这表明连接蛋白可能在淋巴细胞生理学中发挥重要作用。传统上，连接蛋白在组装成间隙连接-细胞间通道时发挥作用。然而，现在有这样一种可能性，即间隙连接半通道（以前被视为间隙连接的质膜前体）也参与小代谢物（如腺苷5'-三磷酸和烟酰胺腺嘌呤二核苷酸(+)）从细胞的释放，这为在淋巴细胞中检测到的连接蛋白开辟了第二种可能的旁分泌功能。越来越多的结构和功能证据表明淋巴细胞间隙连接细胞间通讯可能在免疫突触的复杂信号成分中发挥潜在作用。
