Structural basis for the wobbler mouse neurodegenerative disorder caused by mutation in the Vps54 subunit of the GARP complex.
The multisubunit Golgi-associated retrograde protein (GARP) complex is required for tethering and fusion of endosome-derived transport vesicles to the trans-Golgi network. Mutation of leucine-967 to glutamine in the Vps54 subunit of GARP is responsible for spinal muscular atrophy in the wobbler mouse, an animal model of amyotrophic lateral sclerosis. The crystal structure at 1.7 A resolution of the mouse Vps54 C-terminal fragment harboring leucine-967, in conjunction with comparative sequence analysis, reveals that Vps54 has a continuous alpha-helical bundle organization similar to that of other multisubunit tethering complexes. The structure shows that leucine-967 is buried within the alpha-helical bundle through predominantly hydrophobic interactions that are critical for domain stability and folding in vitro. Mutation of this residue to glutamine does not prevent integration of Vps54 into the GARP complex but greatly reduces the half-life and levels of the protein in vivo. Severely reduced levels of mutant Vps54 and, consequently, of the whole GARP complex underlie the phenotype of the wobbler mouse.
Pérez-Victoria
F Javier
FJ
Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
Abascal-Palacios
Guillermo
G
Tascón
Igor
I
Kajava
Andrey
A
Magadán
Javier G
JG
Pioro
Erik P
EP
Bonifacino
Juan S
JS
Hierro
Aitor
A
D000483:Alleles; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D006367:HeLa Cells; D006801:Humans; D007930:Leucine / Q000378:metabolism; D051379:Mice; D008818:Mice, Neurologic Mutants; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000378:metabolism*; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D019636:Neurodegenerative Diseases / Q000235:genetics*; D009928:Organ Specificity; D055550:Protein Stability; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D033921:Vesicular Transport Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism
D046912:Multiprotein Complexes; D050505:Mutant Proteins; D021122:Protein Subunits; C486749:VPS54 protein, human; D033921:Vesicular Transport Proteins; C486750:Vps54 protein, mouse; D007930:Leucine