Transglutaminase-mediated remodeling of the human erythrocyte membrane skeleton: relevance for erythrocyte diseases with shortened cell lifespan.
Transglutaminase-mediated remodeling of the human erythrocyte membrane skeleton: relevance for erythrocyte diseases with shortened cell lifespan.
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转谷氨酰胺酶介导的人红细胞膜骨架重塑：与细胞寿命缩短的红细胞疾病的相关性。
DOI：
10.1002/9781118105771.ch9
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Chishti,AtharH
中科院分区：
文献类型：
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作者：
Lorand,Laszlo;Murthy,SNPrasanna;Khan,AnwarA;Xue,Weihua;Lockridge,Oksana;Chishti,AtharH
人红细胞转谷氨酰胺酶 (hRBC TG2) 是该酶家族中第一个在细胞-基质相互作用中发挥重要作用的酶，通过证明该蛋白质在从细胞中释放时可以与人纤连蛋白 (FN) 形成极其紧密的复合物。这种结合的化学计量为 2TG2:FN（即 FN 的每个组成链 1TG2），与 TG2 的催化活性无关，并且在存在和不存在 Ca2+ 离子的情况下都会发生 [1–3]。 TG2 的残基 81-106 位于该蛋白第一个结构域的反向平行 β 链 5 和 6 之间的延伸发夹处，似乎对于与 FN 的结合至关重要； Asp94 和 Asp97 突变为 Ala 显着降低了 TG2 与 FN 的结合亲和力。与 TG2 中的序列 88WTATVVDQQDCTLSLQLTT106 相对应的合成肽可抑制 TG2-FN 相互作用以及 TG2 依赖性细胞粘附和扩散 [4]。 FN 的互补结合位点位于该蛋白的 42 kDa 胶原蛋白结合域中，包含基序 I6-II1-II2-I7-I8-I9。该片段对 TG2 的亲和力与各个亲本 FN 链本身一样高 [5]；此外，FN 的 42 kDa 片段可以中和细胞表面 TG2 的功能 [6]。与 TG2 的结合非常特异，因此通过将 FN 的 42 kDa 片段偶联到凝胶基质制成的亲和柱可用于通过单次去除血红蛋白的红细胞裂解物将 hRBC TG2 分离至最高纯度 [5]（图 1A）。该程序用于纯化 TG2 蛋白，在该蛋白上进行了核苷酸结合研究 [7]，并且在非变性电泳中，可以通过从缓慢移动的延伸结构转变为快速移动的紧凑构型来证明与结合 GTP 相关的大构象变化 [8]（图 1B）。
The human red blood cell transglutaminase (hRBC TG2) was the first in this family of enzymes for which an important role in cell–matrix interaction was found by demonstrating that the protein—when released from cells—could form an extremely tight complex with human fibronectin (FN). The binding, with a stoichiometry of 2TG2: FN (ie, 1TG2 per constituent chain of FN), is independent of the catalytic activity of TG2 and occurs in the absence as well as in the presence of Ca2+ ions [1–3]. Residues 81–106 of TG2, located at the extended hairpin between antiparallel β strands 5 and 6 of the first domain of the protein, seem to be essential for binding to FN; mutations of Asp94 and Asp97 to Ala reduce the binding affinity of TG2 to FN significantly. A synthetic peptide, corresponding to the sequence 88WTATVVDQQDCTLSLQLTT106 in TG2, inhibits the TG2–FN interaction, and also TG2-dependent cell adhesion and spreading [4]. The complementary binding sites of FN are located in a 42-kDa collagen-binding domain of the protein, comprising motifs I6-II1-II2-I7-I8-I9. This fragment shows as high an affinity for TG2 as the individual parent FN chains themselves [5]; furthermore, the 42-kDa fragment of FN can neutralize the functions of TG2 on cell surfaces [6]. Binding to TG2 is so specific that an affinity column made by coupling the 42-kDa fragment of FN to a gel matrix can be used for isolating hRBC TG2 to the highest purity with a single passage of hemoglobin-depleted erythrocyte lysate [5](Figure 1A). This procedure was employed for purifying the TG2 protein on which nucleotide-binding studies were carried out [7], and on which the large conformational change—attendant to binding GTP—could be demonstrated by transition from a slowmoving, extended structure to a faster moving, compact configuration in nondenaturing electrophoresis [8](Figure 1B).