Platelet-activating factor acetylhydrolase IB subunit alpha2

PAFAH1B2 encodes the alpha2 catalytic subunit of platelet-activating factor acetylhydrolase type I (PAF-AH I), a cytosolic enzyme that hydrolyzes the acetyl group at the sn-2 position of platelet-activating factor (PAF) and related lipid mediators (UniProt: P68402). The enzyme's activity and substrate specificity depend on its subunit composition; the PAFAH1B2 homodimer preferentially hydrolyzes PAF and certain glycerol phosphorylethanolamine analogs. The protein may also function in male germ cell meiosis and spermiogenesis, though this role remains incompletely characterized.

PAFAH1B2 is expressed in cytosolic compartments and has not been assigned to specific disease categories in UniProt. However, it is relevant to Alzheimer's disease pathology given PAF's known involvement in neuroinflammatory cascades and neurodegeneration.

PAFAH1B2 is upregulated in human post-mortem Alzheimer's disease brain tissue relative to age-matched controls (Chaparral AD proteomics), with a mean log2 fold-change of 0.26 across subcellular fractions in TMT-labeled quantitative proteomics. This modest elevation suggests a potential compensatory or pathogenic response to PAF-mediated neuroinflammation in AD neuropathology.