Arita Ken, Akiyama Masashi, Aizawa Tomoyasu, Umetsu Yoshitaka, Segawa Ikuo, Goto Maki, Sawamura Daisuke, Demura Makoto, Kawano Keiichi, Shimizu Hiroshi
Department of Dermatology, Hokkaido University Graduate School of Medicine, North 15 West 7, Kita-ku, Sapporo 060-8638, Japan.
Am J Pathol. 2006 Aug;169(2):416-23. doi: 10.2353/ajpath.2006.051242.
Connexins (Cxs) are transmembranous proteins that connect adjacent cells via channels known as gap junctions. The N-terminal 21 amino acids of Cx26 are located at the cytoplasmic side of the channel pore and are thought to be essential for the regulation of channel selectivity. We have found a novel mutation, N14Y, in the N-terminal domain of Cx26 in a case of keratitis-ichthyosis-deafness syndrome. Reduced gap junctional intercellular communication was observed in the patient's keratinocytes by the dye transfer assay using scrape-loading methods. The effect of this mutation on molecular structure was investigated using synthetic N-terminal peptides from both wild-type and mutated Cx26. Two-dimensional (1)H nuclear magnetic resonance and circular dichroism measurements demonstrated that the secondary structures of these two model peptides are similar to each other. However, several novel nuclear Overhauser effect signals appeared in the N14Y mutant, and the secondary structure of the mutant peptide was more susceptible to induction of 2,2,2-trifluoroethanol than wild type. Thus, it is likely that the N14Y mutation induces a change in local structural flexibility of the N-terminal domain, which is important for exerting the activity of the channel function, resulting in impaired gap junctional intercellular communication.
连接蛋白(Cxs)是一种跨膜蛋白,通过称为缝隙连接的通道连接相邻细胞。Cx26的N端21个氨基酸位于通道孔的细胞质侧,被认为对通道选择性的调节至关重要。我们在一例角膜炎-鱼鳞病-耳聋综合征患者中发现了Cx26 N端结构域的一种新突变,即N14Y。通过刮擦加载法进行染料转移试验,在患者的角质形成细胞中观察到缝隙连接细胞间通讯减少。使用野生型和突变型Cx2...