C1QBP also known as HABP1 is known to bind the globular heads of C1q molecules and inhibit C1 activation. C1QBP plays a crucial role in the immune response by binding to the globular heads of C1q molecules, thereby inhibiting C1 activation and modulating the complement system. C1QBP is primarily located in vascular endothelial cells, where C1QBP is involved in various physiological processes, including inflammation and immune regulation. C1QBP presence in these cells facilitates the interaction between the complement and coagulation systems, which is essential for maintaining homeostasis and responding to pathogens. Additionally, C1QBP has been identified as a subunit of the pre-mRNA splicing factor SF2/ASF, highlighting C1QBP′s multifunctional nature and importance in cellular processes beyond the immune response.