Functional analyses of VCP protein in neuronal cell death

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Recent molecular analyses on human neurodegenerative disorders have revealed several common features such as accumulation of abnormal protein aggregates, cytoplasmic vacuolizations, neuronal cell death etc. We have analyzed the molecular bases of such disorders especially polyglutamine diseases, and have identified VCP protein, an AAA class ATPase, as a candidate for a sensor for the accumulation of abnormal proteins as well as for a mediator of cell death. Namely, 1)VCP co-localizes with polyglutamine aggregates and other protein aggregates such as Lewy bodies in Parkinson disease, 2)the expression of ATPase activity-negative VCP in nueoronal cells induces ER-derived vacuoles and cell death, 3)several amino acids in VCP are modified by phoshprylations, acetylations and oxidations, 4)such modification can change VCP ATPase activities and its intra cellular localization, 5)especially, oxidized VCP at the 522 cysteine loses its ATPase activities, 6)depending upon the levels of soluble aggregates-prone proteins, VCP can modulate the aggregate formation, indicating dual VCP functions as an aggregate formase and an unfoldase. Further molecular analyses on VCP would lead to clues for further understanding as well as for novel treatments of neurodegenerative disorders such as polyglutamine diseases and Parkinson disease.