Protein tyrosine phosphatase type IVA 2

Protein tyrosine phosphatase type IVA 2 (PTP4A2) is a small serine/threonine phosphatase that catalyzes the dephosphorylation of protein tyrosine residues, with documented roles in cell cycle progression from G1 to S phase during mitosis (UniProt: Q12974). The protein also functions as an inhibitor of geranylgeranyl transferase type II, modulating protein prenylation pathways. At 167 amino acids (19.1 kDa), it is a compact catalytic enzyme with oncogenic potential.

PTP4A2 is broadly expressed across human tissues and has been associated with tumor promotion through its effects on cell cycle regulation (UniProt: Q12974). No prior disease annotations were recorded in the UniProt knowledge base.

PTP4A2 shows decreased abundance in Alzheimer's disease. Proteomic analysis of human post-mortem AD brain tissue compared to age-matched controls revealed downregulation with a mean log2 fold-change of −0.53 (Chaparral AD proteomics), detected across one subcellular fraction in a TMT-labeled discovery proteomics experiment spanning four cellular compartments (P2, P3, S2, S3). The biological significance of reduced PTP4A2 levels in AD pathology remains to be clarified.