Shimotai Yoshitaka, Goto Takanari, Matsuzaki Yoko, Muraki Yasushi, Sugawara Kanetsu, Hongo Seiji
Department of Infectious Diseases, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan.
Department of Microbiology, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694, Japan.
Biochem Biophys Rep. 2015 Jul 8;3:1-6. doi: 10.1016/j.bbrep.2015.07.001. eCollection 2015 Sep.
CM2 is an integral membrane protein encoded by the influenza C virus M gene. To examine the effects of the cytoplasmic tail of CM2 on its biochemical properties, deletion and substitution mutations were introduced into CM2 cytoplasmic tail at residues 47-115, and the expressed CM2 mutants were investigated. Although the cytoplasmic tail is not essential for the oligomerization of CM2, it may affect the degree of oligomerization. The residues 47-48, 67-69, 73-90 and 113-115 were all required for the proper expression of CM2. Pulse-chase experiments suggest that residues 47-48, 67-69, 73-75 and 79-87 stabilize CM2, thereby affecting CM2 expression. The C-terminal region at residues 61-115 is not essential for CM2 transport to the cell surface, and a 14-amino-acid, but not an 11-amino-acid, cytoplasmic tail is sufficient for the cell surface expression of CM2. These results suggest that either certain amino acid sequences or the length of the CM2 cytoplasmic tail are necessary for the proper conformational maturation, stability, expression level and intracellular transport of CM2.
CM2是一种由丙型流感病毒M基因编码的整合膜蛋白。为了研究CM2胞质尾对其生化特性的影响，在CM2胞质尾的47-115位氨基酸处引入了缺失和替换突变，并对表达的CM2突变体进行了研究。虽然胞质尾对于CM2的寡聚化并非必不可少，但它可能会影响寡聚化程度。47-48位、67-69位、73-90位和113-115位氨基酸对于CM2的正确表达都是必需的。脉冲追踪实验表明，47-48位、67-69位、73-75位和79-87位氨基酸可稳定CM2，从而影响CM2的表达。61-115位氨基酸的C末端区域对于CM2转运至细胞表面并非必需，14个氨基酸而非11个氨基酸的胞质尾对于CM2在细胞表面的表达就足够了。这些结果表明，对于CM2的正确构象成熟、稳定性、表达水平和细胞内转运而言，CM2胞质尾的特定氨基酸序列或长度是必要的。
