Rep M, van Dijl J M, Suda K, Schatz G, Grivell L A, Suzuki C K
Department of Molecular Cell Biology, University of Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands.
Science. 1996 Oct 4;274(5284):103-6. doi: 10.1126/science.274.5284.103.
Afg3p and Rca1p are adenosine triphosphate (ATP)-dependent metalloproteases in yeast mitochondria. Cells lacking both proteins exhibit defects in respiration-dependent growth, degradation of mitochondrially synthesized proteins, and assembly of inner-membrane complexes. Defects in growth and protein assembly, but not in degradation, were suppressed by overproduction of yeast mitochondrial Lon, an ATP-dependent serine protease. Suppression by Lon was enhanced by inactivation of the proteolytic site and was prevented by mutation of the ATP-binding site. It is suggested that the mitochondrial proteases Lon, Afg3p, and Rca1p can also serve a chaperone-like function in the assembly of mitochondrial protein complexes.
Afg3p和Rca1p是酵母线粒体中依赖三磷酸腺苷（ATP）的金属蛋白酶。缺乏这两种蛋白质的细胞在呼吸依赖性生长、线粒体合成蛋白质的降解以及内膜复合物的组装方面表现出缺陷。酵母线粒体Lon（一种依赖ATP的丝氨酸蛋白酶）的过量表达抑制了生长和蛋白质组装方面的缺陷，但没有抑制降解方面的缺陷。Lon的蛋白水解位点失活增强了其抑制作用，而ATP结合位点的突变则阻止了这种抑制作用。这表明线粒体蛋白酶Lon、Afg3p和Rca1p在组装线粒体蛋白复合物时也可发挥类似伴侣蛋白的功能。
