Phosphatase Subfamily PAPL

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

Evolution

PAPL subfamily is found in holozoan. It is absent from most arthropoda.

Domain

PAPL 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].