Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Kumamoto 860-0811, Japan.
Biochem Cell Biol. 2010 Feb;88(1):109-17. doi: 10.1139/o09-116.
Cdc48p/p97 is a highly conserved essential AAA protein that is required for many cellular processes, and is identified as a causative gene for an autosomal dominant human disorder, inclusion body myopathy associated with Paget's disease of the bone and frontotemporal dementia (IBMPFD). Cdc48p/p97 is composed of an N-terminal domain, followed by two AAA domains (D1 and D2) whose ATPase activities have been characterized extensively. In this study, effects of mutations on the essential functions of yeast Cdc48p/p97 in vivo were systematically analyzed. IBMPFD-related mutations do not affect the essential functions of Cdc48p/p97. Loss of ATPase activity of D2 leads to loss of function of the protein in vivo. In contrast, ATPase activity of D1 per se is not essential, but a mutation locking D1 in an ATP-bound form is exceptionally lethal. Site-directed and random mutagenesis analyses suggest that the ATP-bound form of D1 changes an inter-domain interaction, thereby perturbing an essential function of Cdc48p/p97.
Cdc48p/p97 是一种高度保守的必需 AAA 蛋白，它参与许多细胞过程，被鉴定为一种常染色体显性遗传人类疾病的致病基因，该病为伴有骨 Paget 病和额颞叶痴呆的包涵体肌病（IBMPFD）。Cdc48p/p97 由一个 N 端结构域组成，其后是两个 AAA 结构域（D1 和 D2），其 ATP 酶活性已得到广泛研究。在这项研究中，系统分析了酵母 Cdc48p/p97 突变对其体内必需功能的影响。IBMPFD 相关突变不影响 Cdc48p/p97 的必需功能。D2 的 ATP 酶活性丧失导致该蛋白在体内丧失功能。相反，D1 的 ATP 酶活性本身不是必需的，但将 D1 锁定在 ATP 结合形式的突变是异常致命的。定点和随机诱变分析表明，D1 的 ATP 结合形式改变了结构域间相互作用，从而扰乱了 Cdc48p/p97 的必需功能。
