Dispensability of the actin-binding site and spectrin repeats for targeting sarcomeric alpha-actinin into maturing Z bands in vivo: implications for in vitro binding studies.
Dispensability of the actin-binding site and spectrin repeats for targeting sarcomeric alpha-actinin into maturing Z bands in vivo: implications for in vitro binding studies.
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肌动蛋白结合位点和血影蛋白重复序列将肌节α-肌动蛋白靶向体内成熟Z带的可分配性：对体外结合研究的影响。
DOI：
10.1006/dbio.1998.8920
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Holtzer,H
中科院分区：
文献类型：
--
作者：
Lin,Z;Hijikata,T;Zhang,Z;Choi,J;Holtzer,S;Sweeney,HL;Holtzer,H
为了探讨肌节α-肌动蛋白(S-α-肌动蛋白)的特定结构域在肌原纤维的组装和维持中的作用，将4个MYC标记的S-α-肌动蛋白多肽导入成肌细胞培养。它们是：(1)全长肌小瘤α-肌动蛋白，(2)仅去除肌动蛋白结合位点的N端缺失(MYC/A−)，(3)仅包含肌动蛋白结合位点的多肽(MYC/A+)，以及(4)去除EF-HAND和Titin结合域的N末端缺失(MYC/EFT−)。与在PtK2细胞中一样，这四个MYC多肽对复制的肌源性细胞具有细胞毒性，但在有丝分裂后的肌管中不具有细胞毒性。在肌管中，四种不同的MYC多肽都被迅速和选择性地结合到正常的Z带中。MYC/A−、MYC/A+和MYC/EFT−被掺入Z带表明：(A)肌动蛋白结合部位，(B)被认为负责反平行二聚化的光谱蛋白重复序列，(C)C端EF-HAND和Titin结合结构域对于将S-α-肌动蛋白/肌动蛋白多肽靶向Z带是必不可少的。这些发现不能从α-Actinin的行为(A)在无细胞系统中的结合分析中或(B)在转基因的非肌肉细胞中表达时预测到。
To explore the roles of specific domains of sarcomeric α-actinin (s-α-actinin) in the assembly and maintenance of striated myofibrils, myogenic cultures were transfected with four MYC-tagged s-α-actinin peptides. They were: (1) full-length sarcomeric α-actinin, (2) an N-terminal deletion that removed the actin-binding site only (MYC/A−), (3) a peptide that consisted of the actin-binding site only (MYC/A+), and (4) an N-terminal deletion that removed the EF-hands and titin-binding domains (MYC/EFT−). While cytotoxic in replicating myogenic cells, as they were in PtK2 cells, the four MYC peptides were not cytotoxic in postmitotic myotubes. In myotubes each of the four different MYC peptides were promptly and selectively incorporated into normal Z bands. The incorporation of MYC/A−, MYC/A+, and MYC/EFT−into Z bands suggests that (a) the actin-binding site, (b) the spectrin-repeats believed to be responsible for anti-parallel dimerization, and (c) the C-terminal EF-hands and titin-binding domains are each dispensable for targeting s-α-actinin/MYC peptides into Z bands. These findings could not have been predicted from the behavior of α-actinin (a) in binding assays in cell-free systems or (b) when expressed in transfected nonmuscle cells.