Protective protein appears to be essential for both the activity of beta-galactosidase and neuraminidase, it associates with these enzymes and exerts a protective function necessary for their stability and activity. This protein is also a carboxypeptidase and can deamidate tachykinins. Defects in CTSA are the cause of galactosialidosis (GSL). A lysosomal storage disease associated with a combined deficiency of beta-galactosidase and neuraminidase, secondary to a defect in cathepsin A. All patients have clinical manifestations typical of a lysosomal disorder, such as coarse facies, cherry red spots, vertebral changes, foam cells in the bone marrow, and vacuolated lymphocytes. Three phenotypic subtypes are recognized. The early infantile form is associated with fetal hydrops, edema, ascites, visceromegaly, skeletal dysplasia, and early death. The late infantile type is characterized by hepatosplenomegaly, growth retardation, cardiac involvement, and a normal or mildly affected mental state. The juvenile/adult form is characterized by myoclonus, ataxia, angiokeratoma, mental retardation, neurologic deterioration, absence of visceromegaly, and long survival. Belongs to the peptidase S10 family. Note: This description may include information from UniProtKB.
Protein type: EC 18.104.22.168; Endoplasmic reticulum; Mitochondrial; Protease
Biological Process: glycosphingolipid metabolic process; intracellular protein transport; neutrophil degranulation; positive regulation of catalytic activity; proteolysis; proteolysis involved in cellular protein catabolic process; regulation of protein stability