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Protein Page:
VMA21 (human)
p Phosphorylation
ac Acetylation
me Methylation
m1 Mono-methylation
m2 Di-methylation
m3 Tri-methylation
ub Ubiquitylation
sm Sumoylation
ne Neddylation
gl O-GlcNAc
ga O-GalNAc
pa Palmitoylation
ad Adenylation
sn S-Nitrosylation
ca Caspase cleavage
sc Succinylation

VMA21 Required for the assembly of the V0 complex of the vacuolar ATPase (V-ATPase) in the endoplasmic reticulum. Defects in VMA21 are the cause of X-linked myopathy with excessive autophagy (MEAX). 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. Belongs to the VMA21 family. 2 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.
Protein type: Membrane protein, multi-pass; Membrane protein, integral
Chromosomal Location of Human Ortholog: Xq28
Cellular Component: COPII vesicle coat; endoplasmic reticulum membrane; lysosome
Biological Process: regulation of ATPase activity
Disease: Myopathy, X-linked, With Excessive Autophagy
Reference #:  Q3ZAQ7 (UniProtKB)
Alt. Names/Synonyms: MEAX; MGC125514; MGC125516; MGC131652; Myopathy with excessive autophagy protein; Vacuolar ATPase assembly integral membrane protein VMA21; VMA21; VMA21 vacuolar H+-ATPase homolog (S. cerevisiae); XMEA
Gene Symbols: VMA21
Molecular weight: 11,354 Da
Basal Isoelectric point: 6.56  Predict pI for various phosphorylation states
Select Structure to View Below


Protein Structure Not Found.

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Modification Sites and Domains Show Modification Legend
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Modification Sites in Parent Protein, Orthologs, and Isoforms Show Modification Legend

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LTP: The number of records in which this modification site was determined using site-specific methods. SS methods include amino acid sequencing, site-directed mutagenesis, modification site-specific antibodies, specific MS strategies, etc.


HTP: The number of records in which this modification site was assigned using ONLY proteomic discovery-mode mass spectrometry.



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