Predicted to enable complement binding activity. Predicted to be involved in several processes, including negative regulation of complement activation, classical pathway; regulation of opsonization; and response to symbiotic bacterium. Predicted to act upstream of or within binding activity of sperm to zona pellucida. Predicted to be located in acrosomal vesicle; cell body; and plasma membrane. Predicted to be part of zona pellucida receptor complex. Predicted to be active in extracellular space. Human ortholog(s) of this gene implicated in COVID-19. Orthologous to human C4BPA (complement component 4 binding protein alpha). [provided by Alliance of Genome Resources, Apr 2022]