Phosphatase Subfamily ACP5

Phosphatase Classification: Fold MTDP:Superfamily MTDP: Family PAP: ACP5

ACP5 subfamily is found in most eukaryotes. Human ACP5 hydrolyzes a variety of phosphomonoesters at acid pH in vitro. It also show phosphatase activity towards protein osteopontin, and mannose 6-phosphate modification on lysosomal proteins.

Evolution

ACP5 is present in most eukaryotic groups, such as animals and plants. It is found in few fungi, though. ACP5 is also observed in some prokaryotes. ACP5 subfamily has a single member in human genome, which is also called tartrate resistant acid phosphatase (TRAP) or uteroferrin. Fruit fly has a single ACP5 gene (CG1637), which encodes at least five protein isoforms. C. elegant and nematostella have multiple ACP5 genes, and some locate close to each other, even in the form of tandem duplications.

Domain

ACP5 has a phosphatase domain and a signal peptide cleavage site on N-terminus.

Function

Human ACP5 hydrolyzes a variety of phosphomonoesters at acid pH in vitro. ACP5 also acts as an osteopontin phosphatase [1]. Osteopontin is a protein that in humans is encoded by the SPP1 gene (secreted phosphoprotein 1). Osteopontin is involved in many biological processes including biomineralization, bone remodeling, immune functions in heart, chemotaxis, cell activation, apoptosis.

ACP5 also dephosphorylate mannose 6-phosphate modification on lysosomal proteins. Most newly synthesized proteins destined for the lysosome reach this location via a specific intracellular pathway. In the Golgi, a phosphotransferase specifically labels lysosomal proteins with mannose 6-phosphate (Man-6-P). This modification is recognized by receptors that target the lysosomal proteins to the lysosome where, in most cell types, the Man-6-P recognition marker is rapidly removed [2].

References

Error fetching PMID 14584906:
Error fetching PMID 18940929: