Localization of sequences within the C-terminal domain of the cystic fibrosis transmembrane conductance regulator which impact maturation and stability
Localization of sequences within the C-terminal domain of the cystic fibrosis transmembrane conductance regulator which impact maturation and stability
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DOI：
10.1074/jbc.m003672200
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发表时间：
2001-01-12
影响因子：
4.8
通讯作者：
Riordan, JR
中科院分区：
文献类型：
--
作者：
Gentzsch, M;Riordan, JR
第二核苷酸结合结构域的 100 个残基结构域 C 端内的一些与疾病相关的截短使成熟蛋白不稳定（Haardt, M,, Benharouga, M,, Lechardeur, D,, Kartner, N, 和 Lukacs, G;. L, (1999) J, Biol. Chem, 274, 21873-21877），我们现在已经鉴定C 端结构域中的三个短寡肽区域以不同方式影响囊性纤维化跨膜电导调节因子 (CFTR) 的成熟和稳定性，发现由残基 1413-1416 (FLVI) 形成的高度保守的疏水斑块（区域 I）对于成熟蛋白的稳定性至关重要。蛋白质缩短了 81 个氨基酸 (1400X)，从而严重降低了新生链的稳定性。这种加速降解对蛋白酶体抑制剂敏感，但不受布雷菲德菌素 A 的影响，表明它发生在内质网。位置 1400 至 1404（区域 II）的五个残基通常以位置而非序列特异性方式维持新生 CFTR 稳定性。由残基1390至1394构成的第三调节区(III)使蛋白质不稳定。因此，新生形式在进一步截断回残基 1390 或 1380 时恢复稳定性，从而允许一定程度的成熟和细胞表面低水平的环 AMP 刺激的氯离子通道活性。因此，虽然不是绝对必要的，但 C 端结构域强烈调节 CFTR 的生物发生和成熟。
Some disease-associated truncations within the 100-residue domain C-terminal of the second nucleotide-binding domain destabilize the mature protein (Haardt, M,, Benharouga, M,, Lechardeur, D,, Kartner, N,, and Lukacs, G;. L, (1999) J, Biol. Chem, 274, 21873-21877), We now have identified three short oligopeptide regions in the C-terminal domain which impact cystic fibrosis transmembrane conductance regulator (CFTR) maturation and stability in different ways, A highly conserved hydrophobic patch (region I) formed by residues 1413-1416 (FLVI) was found to be crucial for the stability of the mature protein. Nascent chain stability was severely decreased by shortening the protein by 81 amino acids (1400X). This accelerated degradation was sensitive to proteasome inhibitors but not influenced by brefeldin A, indicating that it occurred at the endoplasmic reticulum. The five residues at positions 1400 to 1404 (region II) normally maintain nascent CFTR stability in a positional rather than a sequence-specific manner. A third modulating region (III) constituted by residues 1390 to 1394 destabilizes the protein. Hence the nascent form regains stability on further truncation back to residues 1390 or 1380, permitting some degree of maturation and a low level of cyclic AMP-stimulated chloride channel activity at the cell surface. Thus while not absolutely essential, the C-terminal domain strongly modulates the biogenesis and maturation of CFTR.