title: Oligomerization of Cysteine String Protein alpha mutants causing adult neuronal ceroid lipofuscinosis.
abstract: Cysteine String Protein alpha (CSPα) is a palmitoylated, synaptic vesicle co-chaperone that is essential for neuroprotection. Two mutations in CSPα - L115R and L116Δ - cause adult neuronal ceroid lipofuscinosis (ANCL), a dominantly-inherited neurodegenerative disease. To elucidate the pathogenesis of ANCL, the intrinsic biochemical properties of human wildtype (WT) and disease mutant CSPα were examined. Mutant proteins purified from Escherichia coli exhibited high potency to oligomerize in a concentration, temperature, and time dependent manner, with L115R possessing the greatest potency. When freshly purified, ANCL mutant proteins displayed normal co-chaperone activity and substrate recognition similar to WT. However, co-chaperone activity was impaired for both CSPα mutants upon oligomerization. When WT and mutant CSPα were mixed together they co-oligomerized leading to an overall decrease of co-chaperone activity. The oligomerization properties of ANCL mutants were faithfully replicated in HEK 293T cells. Interestingly, the oligomers were covalently tagged by ubiquitination instead of palmitoylation. Taken together, ANCL mutations result in both a gain and partial loss-of-function.
authors: Program for Cellular Neuroscience, Neurodegeneration and Repair, Department of Neurology, Yale School of Medicine, New Haven, CT 06536, USA. Electronic address: yongquan.zhang@yale.edu.
authors: Yong-Quan
authors: YQ
authors: Zhang
authors: Program for Cellular Neuroscience, Neurodegeneration and Repair, Department of Neurology, Yale School of Medicine, New Haven, CT 06536, USA; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06536, USA. Electronic address: sreeganga.chandra@yale.edu.
authors: Sreeganga S
authors: SS
authors: Chandra
keywords: ATPase; Heat shock cognate; J domain; Lysosomal storage disease; Synapse maintenance