Phospholipase A2 Receptor 1 (PLA2R1) is a type I transmembrane glycoprotein belonging to the mannose receptor family, primarily expressed on human podocytes. It serves as the specific receptor for secretory phospholipase A2 (sPLA2) and plays crucial roles in phospholipid metabolism and cellular signaling. Structurally, it contains an extracellular region with multiple functional domains including a cysteine-rich domain, fibronectin type II domain, and eight C-type lectin-like domains. Discovered as the major autoantigen in primary membranous nephropathy (accounting for 70-80% of cases), anti-PLA2R1 antibodies have become key diagnostic markers. Beyond nephrology, PLA2R1 is involved in various biological processes including inflammation, cell proliferation and apoptosis.Besides,Cytosolic Phospholipase A2 (PLA2G4) has been identified as an interactor of PLA2R1, thus a functional binding ELISA assay was conducted to detect the interaction of recombinant mouse PLA2R1 and recombinant human PLA2G4 .Briefly, biotin-linked PLA2R1 were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100μl were then transferred to PLA2G4-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST 3 times and incubation with Streptavidin-HRP for 30min, then wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50μl stop solution to the wells and read at 450nm immediately. The binding activity of recombinant mouse PLA2R1 and recombinant human PLA2G4 was shown in Figure 1, the EC50?for this effect is 0.11 μg/mL.