Metalloprotease-mediated OPA1 processing is modulated by the mitochondria) membrane potential
Metalloprotease-mediated OPA1 processing is modulated by the mitochondria) membrane potential
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DOI：
10.1042/bc20070110
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发表时间：
2008-05-01
影响因子：
2.7
通讯作者：
Rojo, Manuel
中科院分区：
文献类型：
--
作者：
Guillery, Olwenn;Malka, Florence;Rojo, Manuel
背景资料。人OPA 1（视神经萎缩1型）是一种线粒体IMS（膜间隙）的动力蛋白相关蛋白，参与膜融合和重塑。类似于其酵母直向同源物Mgm 1 p，其存在于由丝氨酸蛋白酶Pcp 1 p/Rbd 1 p产生的两种同种型中，OPA 1存在于由选择性剪接和加工产生的各种同种型中。本文主要研究了OPA 1的蛋白酶加工。我们发现，各种哺乳动物细胞类型显示出相似的OPA 1亚型模式[两种L-OPA 1（OPA 1的长亚型）和三种S-OPA 1（OPA 1的短亚型）]，并且内膜电位的丧失，但不是氧化磷酸化或糖酵解的抑制，诱导L-OPA 1快速和完全加工为S-OPA 1。在分离的线粒体中，OPA 1的加工被重金属螯合剂抑制，指向线粒体金属蛋白酶的加工。OPA 1亚型及其加工动力学的模式是正常的线粒体缺乏丝氨酸蛋白酶PARL（早老相关菱形样蛋白）-人类直系同源物的Pcp 1/Rbd 1-和细胞携带纯合突变SPG 7（痉挛性截瘫7型），编码基质导向金属蛋白酶paraplegin的基因。与此相反，OPA 1加工动力学延迟后敲低YME 1 L（人yme 1样蛋白），IMS导向的金属蛋白酶。OPA 1加工过程中也刺激细胞凋亡，但抑制这种处理并不影响OPA 1和细胞色素c的凋亡释放。最后，我们发现所有OPA 1亚型都与Mfn 1（线粒体融合蛋白1）和Mfn 2相互作用，并且这些相互作用不受Delta Psi m（线粒体内膜电位）耗散或OPA 1加工的影响。金属蛋白酶介导的OPA 1加工受内膜电位调节，并且可能由YME 1 L蛋白酶介导。
Background information. Human OPA1 (optic atrophy type 1) is a dynamin-related protein of the mitochondrial IMS (intermembrane space) involved in membrane fusion and remodelling. Similarly to its yeast orthologue Mgm1p that exists in two isoforms generated by the serine protease Pcp1p/Rbd1p, OPA1 exists in various isoforms generated by alternative splicing and processing. In the present paper, we focus on protease processing of OPA1.Results. We find that various mammalian cell types display a similar pattern of OPA1 isoforms [two L-OPA1 (long isoforms of OPA1) and three S-OPA1 (short isoforms of OPA1)] and that loss of the inner membrane potential, but not inhibition of oxidative phosphorylation or glycolysis, induces rapid and complete processing of L-OPA1 to S-OPA1. In isolated mitochondria, OPA1 processing was inhibited by heavy-metal chelators, pointing to processing by a mitochondrial metalloprotease. The pattern of OPA1 isoforms and its processing kinetics were normal in mitochondria devoid of the serine protease PARL (presenilins-associated rhomboid-like protein)-the human orthologue of Pcp1/Rbd1 - and in cells from patients carrying homozygous mutations in SPG7 (spastic paraplegia type 7), a gene encoding the matrix-oriented metalloprotease paraplegin. In contrast, OPA1 processing kinetics were delayed upon knock-down of YME1L (human yme1-like protein), an IMS-oriented metal loprotease. OPA1 processing was also stimulated during apoptosis, but inhibition of this processing did not affect apoptotic release of OPA1 and cytochrome c. Finally, we show that all OPA1 isoforms interact with Mfn1 (mitofusin 1) and Mfn2 and that these interactions are not affected by dissipation of Delta Psi m (inner mitochondrial membrane potential) or OPA1 processing.Conclusions. Metalloprotease-mediated processing of OPA1 is modulated by the inner membrane potential and is likely to be mediated by the YME1L protease.