# Molecular Insights into IAHSP: Influence of the R1611W Mutation on the VPS9 Domain of Alsin

## TL;DR

This study explores how a specific mutation in the alsin protein affects its VPS9 domain, potentially causing a rare neurodegenerative disease.

## Contribution

The study provides new insights into the structural and functional impact of the R1611W mutation on the VPS9 domain of alsin.

## Key findings

- The R1611W mutation alters the conformational structure of the VPS9 domain.
- The mutation affects the protein's ability to oligomerize and perform its GEF function.
- These findings help explain the disease mechanisms in IAHSP.

## Abstract

Mutations of the
alsin protein have been linked to infantile-onset
ascending hereditary spastic paraplegia (IAHSP), a rare neurodegenerative
disease. More precisely, the pathological R1611W mutation has been
identified in the Vacuolar Protein Sorting 9 (VPS9) domain, which
acts as a guanine nucleotide exchange factor (GEF) for Rab5. This
mutation results in the expression of tryptophan instead of arginine
that alters the oligomeric state of alsin and its GEF functions. Insights
into the conformational structure of the wild-type or mutant VPS9
domain may help elucidate the mechanisms involved in the onset of
the disease. In this study, we combined in vitro and in silico approaches to elucidate the structure and understand
the effects of the R1611W mutation on the isolated VPS9 domain of
alsin. This mutation induces conformational changes that alter the
local structure of the protein and its ability to oligomerize. This
study lays the groundwork for understanding how R1611W alters the
VPS9 domain function.