PT  - JOURNAL ARTICLE
AU  - R.E.N. van der Welle
AU  - R. Jobling
AU  - C. Burns
AU  - P. Sanza
AU  - C. ten Brink
AU  - A. Fasano
AU  - L. Chen
AU  - F.J. Zwartkruis
AU  - S. Zwakenberg
AU  - E.F. Griffin
AU  - J. van der Beek
AU  - T. Veenendaal
AU  - N. Liv
AU  - S. Blaser
AU  - C. Sepulveda
AU  - A.M. Lozano
AU  - G. Yoon
AU  - C.S. Asensio
AU  - G.A. Caldwell
AU  - K.A. Caldwell
AU  - D. Chitayat
AU  - J. Klumperman
TI  - <em>VPS41</em> recessive mutation causes ataxia and dystonia with retinal dystrophy and mental retardation by inhibiting HOPS function and mTORC1 signaling
AID  - 10.1101/2019.12.18.867333
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 2019.12.18.867333
4099  - http://biorxiv.org/content/early/2019/12/20/2019.12.18.867333.short
4100  - http://biorxiv.org/content/early/2019/12/20/2019.12.18.867333.full
AB  - The vacuolar protein sorting protein 41 (VPS41) is a neuroprotective protein in models of Parkinson’s disease (PD). As part of the HOPS (Homotypic fusion and Protein Sorting) complex, VPS41 regulates fusion of lysosomes with late endosomes and autophagosomes. Independent of HOPS, VPS41 regulates transport of newly synthesized lysosomal membrane proteins and secretory proteins. Here we report two brothers with compound heterozygous mutations in VPS41 (VPS41R662* and VPS41S285P), born to healthy and non-consanguineous parents. Both patients displayed transient retinal dystrophy, ataxia and dystonia, with brain MRI findings of cerebellar atrophy and a thin saber-shape corpus callosum. Patient-derived fibroblasts contained enzymatically active lysosomes that were poorly reached by endocytic cargo and failed to attract the mTORC1 complex. Consequently, transcription factor TFE3, a driver of autophagy and lysosomal genes, showed continuous nuclear localization which resulted in elevated LC3-II levels and an impaired response to nutrient starvation. CRISPR/CAS VPS41 HeLa knockout cells showed a similar phenotype that could be rescued by wildtype VPS41 but not by VPS41S285P or VPS41R662*. mTORC1 inhibition was also seen after knockout of HOPS subunits VPS11 or VPS18. Regulated neuropeptide secretion in PC12 VPS41 knockout cells was rescued by VPS41S285P expression, indicating that this HOPS-independent function was preserved. Co-expression of the VPS41S285P and VPS41R662* variants in a C. elegans model of PD abolished the protective effect of VPS41 against α-synuclein-induced neurodegeneration. We conclude that both disease-associated VPS41 variants specifically abrogate HOPS function, which leads to a delay in endocytic cargo delivery to lysosomes, mTORC1 inhibition and irresponsiveness to autophagic clues. Our studies signify a link between HOPS function and mTORC1 signaling and imply that HOPS function is required for the neuroprotective effect of VPS41 in PD.