跨膜结构域序列在糖蛋白介导的膜融合中的作用。
The role of the membrane-spanning domain sequence in glycoprotein-mediated membrane fusion.
作者信息
Taylor G M, Sanders D A
机构信息
Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1392, USA.
出版信息
Mol Biol Cell. 1999 Sep;10(9):2803-15. doi: 10.1091/mbc.10.9.2803.
The role of glycoprotein membrane-spanning domains in the process of membrane fusion is poorly understood. It has been demonstrated that replacing all or part of the membrane-spanning domain of a viral fusion protein with sequences that encode signals for glycosylphosphatidylinositol linkage attachment abrogates membrane fusion activity. It has been suggested, however, that the actual amino acid sequence of the membrane-spanning domain is not critical for the activity of viral fusion proteins. We have examined the function of Moloney murine leukemia virus envelope proteins with substitutions in the membrane-spanning domain. Envelope proteins bearing substitutions for proline 617 are processed and incorporated into virus particles normally and bind to the viral receptor. However, they possess greatly reduced or undetectable capacities for the promotion of membrane fusion and infectious virus particle formation. Our results imply a direct role for the residues in the membrane-spanning domain of the murine leukemia virus envelope protein in membrane fusion and its regulation. They also support the thesis that membrane-spanning domains possess a sequence-dependent function in other protein-mediated membrane fusion events.
糖蛋白跨膜结构域在膜融合过程中的作用目前尚不清楚。研究表明，用编码糖基磷脂酰肌醇连接附着信号的序列取代病毒融合蛋白的全部或部分跨膜结构域会消除膜融合活性。然而，有人提出跨膜结构域的实际氨基酸序列对病毒融合蛋白的活性并不关键。我们研究了莫洛尼鼠白血病病毒包膜蛋白在跨膜结构域发生替换后的功能。携带脯氨酸617替换的包膜蛋白能正常加工并整合到病毒颗粒中，并与病毒受体结合。然而，它们促进膜融合和感染性病毒颗粒形成的能力大大降低或无法检测到。我们的结果表明鼠白血病病毒包膜蛋白跨膜结构域中的残基在膜融合及其调控中具有直接作用。它们还支持这样的论点，即跨膜结构域在其他蛋白质介导的膜融合事件中具有序列依赖性功能。
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