Short class I major histocompatibility complex cytoplasmic tails differing in charge detect arbiters of lateral diffusion in the plasma membrane
Short class I major histocompatibility complex cytoplasmic tails differing in charge detect arbiters of lateral diffusion in the plasma membrane
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DOI：
10.1016/s0006-3495(04)74341-6
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发表时间：
2004-05-01
影响因子：
3.4
通讯作者：
Zúñiga, MC
中科院分区：
文献类型：
--
作者：
Capps, GG;Pine, S;Zúñiga, MC
I类主要组织相容性复合体（MHC）分子在细胞膜上的定向和布朗运动与抗原呈递有关。先前的研究表明，I类MHC胞质尾区对分子的扩散施加限制。在这里，我们使用单粒子跟踪来研究野生型小鼠H-2L（d）I类MHC分子和7个胞质尾变体的迁移率。其中六种变体具有四个或七个残基的细胞质尾（净电荷不同），一种是无尾的，但所有这些变体都容易受到膜结构域的限制。然而，将胞质尾截短为0-4个残基降低了表现出受限扩散的颗粒的比例，并增加了表现出简单扩散的比例。特别是对于截短的突变体（0-7个残基的尾长），许多粒子具有复杂的轨迹，并且在整个观察期间不以恒定速度或相同的扩散模式移动。无尾H-2L（d）突变体的几个颗粒显示出一种定向扩散类型，这在其他H-2L（d）突变体中很少观察到。两者合计，这些数据表明，即使短的胞质尾可以显着影响I类MHC的流动性和胞质尾的长度和序列影响分子在膜中的扩散。
Directed and Brownian movement of class I major histocompatibility complex (MHC) molecules on cell membranes is implicated in antigen presentation. Previous studies indicated that the class I MHC cytoplasmic tail imposes constraints on the molecule's diffusion. Here we used single particle tracking to study the mobility of the wild-type mouse H-2L(d) class I MHC molecule and of seven cytoplasmic tail variants. Six of the variants have cytoplasmic tails of four or seven residues (differing in net charge), and one is tailless, yet all are susceptible to confinement in membrane domains. However, truncation of the cytoplasmic tail to 0-4 residues decreases the proportion of particles exhibiting confined diffusion and increases the proportion exhibiting simple diffusion. Particularly for the truncated mutants (tail length of 0-7 residues), many of the particles have complex trajectories and do not move at a constant speed or in the same mode of diffusion throughout the observation period. Several particles of the tailless H-2L(d) mutant display a type of directed diffusion that is rarely observed for other H-2L(d) mutants. Taken together, these data show that even short cytoplasmic tails can influence markedly class I MHC mobility and that cytoplasmic tail length and sequence affect the molecule's diffusion in the membrane.