Phosphatase Subfamily ACP5
Phosphatase Classification: Fold MTDP:Superfamily MTDP: Family PAP: ACP5
Contents
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. However, in many other lineages such insect, nematodes and amoebazoan, multiple members are present in the genomes.
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
- Andersson G, Ek-Rylander B, Hollberg K, Ljusberg-Sjölander J, Lång P, Norgård M, Wang Y, and Zhang SJ. TRACP as an osteopontin phosphatase. J Bone Miner Res. 2003 Oct;18(10):1912-5. DOI:10.1359/jbmr.2003.18.10.1912 |
- Sun P, Sleat DE, Lecocq M, Hayman AR, Jadot M, and Lobel P. Acid phosphatase 5 is responsible for removing the mannose 6-phosphate recognition marker from lysosomal proteins. Proc Natl Acad Sci U S A. 2008 Oct 28;105(43):16590-5. DOI:10.1073/pnas.0807472105 |
