Characterizing the VAC14 multimeric state

PtdIns(3,5)₂ is involved in a number of cellular processes, such as the regulation of endolysosome morphology and membrane trafficking, autophagy and ion transport. In mammala, PtdIns(3,5)₂ deficiency results in vacuolation most notable in the neurons of the central and peripheral nervous system. This can potentially block the trafficking of neurotransmitters leading to a progression of neurodegeneration diseases such as amyotrophic lateral sclerosis and Charcot-Marie-Tooth disease. PtdIns(3,5)₂ is synthesized by the Fab1/PIKfyve lipid kinase and degraded by the Fig4/Sac3 lipid phosphatase. Fab1 and Fig4 are found in a complex with its regulator, the Fac14/ArPIKfyve adaptor protein. The aim of this study was to identify the multimeric state of recombinant Vac14 in order to help elucidate the importance of the Vac14 multimer in the regulation of PtdIns(3,5)₂. The result of this study indicated that recombinant Vac14 forms a homodimer and/or homotrimer.