ID:VMA21_HUMAN DESCRIPTION: RecName: Full=Vacuolar ATPase assembly integral membrane protein VMA21; AltName: Full=Myopathy with excessive autophagy protein; FUNCTION: Required for the assembly of the V0 complex of the vacuolar ATPase (V-ATPase) in the endoplasmic reticulum. SUBUNIT: Associates with the V0 complex of the vacuolar ATPase (V- ATPase). SUBCELLULAR LOCATION: Endoplasmic reticulum membrane; Multi-pass membrane protein. Endoplasmic reticulum-Golgi intermediate compartment membrane; Multi-pass membrane protein. Cytoplasmic vesicle, COPII-coated vesicle membrane; Multi-pass membrane protein. DISEASE: Defects in VMA21 are the cause of X-linked myopathy with excessive autophagy (MEAX) [MIM:310440]. MEAX is a childhood-onset disease characterized by progressive vacuolation and atrophy of skeletal muscle. It is inherited in recessive fashion, affecting boys and sparing carrier females. Onset is in childhood, and patients exhibit weakness of the proximal muscles of the lower extremities, progressing slowly to involve other skeletal muscle groups over time. Other organs including the heart and brain are clinically unaffected. Phenotype is due to an increase of lysosomal pH from 4.7 to 5.2, which reduces lysosomal degradative ability and blocks autophagy. This reduces cellular free amino acids, which up-regulates the mTOR pathway and mTOR-dependent macroautophagy, resulting in proliferation of large and ineffective autolysosomes that engulf sections of cytoplasm, merge together, and vacuolate the cell. SIMILARITY: Belongs to the VMA21 family. CAUTION: Protein characterization data are from PubMed:19379691. Due to a number of errors in the figure panels, the article has been retracted but the authors stand by the validity of the main results and conclusions (PubMed:20873370).
The RNAfold program from the Vienna RNA Package is used to perform the secondary structure predictions and folding calculations. The estimated folding energy is in kcal/mol. The more negative the energy, the more secondary structure the RNA is likely to have.
ModBase Predicted Comparative 3D Structure on Q3ZAQ7
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Orthologous Genes in Other Species
Orthologies between human, mouse, and rat are computed by taking the best BLASTP hit, and filtering out non-syntenic hits. For more distant species reciprocal-best BLASTP hits are used. Note that the absence of an ortholog in the table below may reflect incomplete annotations in the other species rather than a true absence of the orthologous gene.
US Server
Sequence and Links to Tools and Databases 
Common Gene Haplotype Alleles 
