Isoform 2 of Basigin

Basigin (BSG) isoform 2 is a multifunctional cell-surface glycoprotein that acts as a signaling receptor for cyclophilins and serves as a chaperone for monocarboxylate transporters, directing them to the plasma membrane (UniProt: P35613-2). The protein also functions as a coreceptor for vascular endothelial growth factor receptor 2, promoting angiogenesis and endothelial cell signaling. Additionally, BSG plays roles in immune cell adhesion and chemotaxis through cyclophilin-dependent pathways.

Beyond its vascular and metabolic functions, BSG has documented roles in microbial pathogenesis, serving as an entry receptor or facilitator for several pathogens including malaria parasites, SARS-CoV-2, HIV-1, measles virus, and cytomegalovirus (UniProt: P35613-2). The protein is notably involved in tumor-associated processes, regulating matrix metalloproteinase production and neoangiogenesis.

In Alzheimer's disease, BSG isoform 2 is consistently upregulated in human post-mortem AD brain tissue compared to age-matched controls (Chaparral AD proteomics). The mean log2 fold-change is 0.606, indicating modest but consistent elevation across the analyzed subcellular fractions. This upregulation suggests potential involvement in AD-associated vascular dysfunction or neuroinflammatory processes.