Alternative titles; symbolsPHOSPHOLIPASE A2, SECRETED, GROUP XIIBSPLA2-GXIIBGXIIBHGNC Approved Gene Symbol: PLA2G12BCytogenetic location: 10q22.1 Genomic coo...
Alternative titles; symbols
HGNC Approved Gene Symbol: PLA2G12B
Cytogenetic location: 10q22.1 Genomic coordinates (GRCh38): 10:72,934,761-72,955,043 (from NCBI)
Phospholipase A2 (PLA2) enzymes catalyze hydrolysis of glycolipids to release free fatty acids and lysophospholipids. PLA2G12B belongs to the PLA2 family, but it is catalytically inactive due to an amino acid change in its active site and has altered phospholipid-binding properties (Rouault et al., 2003).
▼ Cloning and Expression
By searching databases for secreted PLA2 (sPLA2) homologs, followed by RT-PCR, Rouault et al. (2003) cloned human and mouse PLA2G12B, which they called GXIIB. The predicted 195-amino acid human protein shares 90% identity with the mouse protein and 40% identity with human PLA2G12A (611652). It contains a 19-amino acid signal peptide and 14 cysteines, but it lacks N-glycosylation sites and has a leucine in place of the canonical histidine in its active site. PLA2G12B is conserved in vertebrates, but not in invertebrates. SDS-PAGE revealed a 20-kD PLA2G12B protein, consistent with the calculated molecular mass of the mature protein. Northern blot analysis detected 1.4- and 6.5-kb PLA2G12B transcripts in liver, kidney, skeletal muscle, and heart. Expression of PLA2G12B was significantly weaker in tumors of kidney, liver, and small intestine compared with matched normal tissues. PLA2G12B expression varied in cancer cell lines.
▼ Gene Function
Rouault et al. (2003) found that recombinant PLA2G12B lacked enzymatic activity and had poor phospholipid-binding properties, suggesting it may be comparable to inactive snake venom sPLA2-like proteins.
▼ Gene Structure
Rouault et al. (2003) determined that the PLA2G12B gene contains at least 4 exons and spans 20 kb.
By genomic sequence analysis, Rouault et al. (2003) mapped the PLA2G12B gene to human and mouse chromosome 10.