Endoplasmic Reticulum-associated Degradation (ERAD) and Autophagy Cooperate to Degrade Polymerogenic Mutant Serpins
Endoplasmic Reticulum-associated Degradation (ERAD) and Autophagy Cooperate to Degrade Polymerogenic Mutant Serpins
复制标题
DOI：
10.1074/jbc.m109.027102
复制
发表时间：
2009-08-21
影响因子：
4.8
通讯作者：
Lomas, David A.
中科院分区：
文献类型：
--
作者：
Kroeger, Heike;Miranda, Elena;Lomas, David A.
丝氨酸蛋白酶抑制剂病是一个家族的疾病，其特征在于在内质网内积累突变蛋白的有序聚合物。他们是一个多样化的群体，包括α（1）-抗胰蛋白酶缺乏症和遗传性痴呆家族性脑病与neuroserpin包涵体或FENIB。我们已经使用COS 7细胞和小鼠胚胎成纤维细胞、条件性表达野生型和突变型神经丝氨酸蛋白酶抑制剂的PC 12细胞系以及FENIB的苍蝇模型的瞬时转染来评估野生型和突变型丝氨酸蛋白酶抑制剂的细胞处理。通过使用聚合物特异性单克隆抗体，我们表明，突变neuroserpin形成聚合物后，延迟至少30分钟，聚合物可以清除PC 12细胞系和从大脑中的FENIB苍蝇模型。在稳定状态下，单体和聚合状态下的细胞内聚合G392 E突变体神经丝氨酸蛋白酶抑制剂的分数是相当的。MG 132对蛋白酶体的抑制作用表明，突变型神经丝氨酸蛋白酶抑制剂和α（1）-抗胰蛋白酶主要通过内质网相关降解（ERAD）降解。药理学和遗传学抑制表明，自噬是负责野生型和突变体丝氨酸蛋白酶抑制剂的批量周转，但可以通过雷帕霉素刺激，以补偿蛋白酶体抑制。这些研究结果的治疗serpinopathies的意义进行了讨论。
The serpinopathies are a family of diseases characterized by the accumulation of ordered polymers of mutant protein within the endoplasmic reticulum. They are a diverse group including alpha(1)-antitrypsin deficiency and the inherited dementia familial encephalopathy with neuroserpin inclusion bodies or FENIB. We have used transient transfection of COS7 cells and mouse embryonic fibroblasts, PC12 cell lines that conditionally express wild type and mutant neuroserpin and fly models of FENIB to assess the cellular handling of wild type and mutant serpins. By using a polymer-specific monoclonal antibody, we show that mutant neuroserpin forms polymers after a delay of at least 30 min and that polymers can be cleared in PC12 cell lines and from the brain in a fly model of FENIB. At steady state, the fractions of intracellular polymerogenic G392E mutant neuroserpin in the monomeric and polymeric states are comparable. Inhibition of the proteasome with MG132 reveals that both mutant neuroserpin and alpha(1)-antitrypsin are degraded predominantly by endoplasmic reticulum-associated degradation (ERAD). Pharmacological and genetic inhibitions demonstrate that autophagy is responsible for bulk turnover of wild type and mutant serpins, but can be stimulated by rapamycin to compensate for proteasome inhibition. The significance of these findings to the treatment of serpinopathies is discussed.