Defensin 1 and defensin 2 have antibacterial, fungicide and antiviral activities. Has antimicrobial activity against Gram-negative and Gram-positive bacteria. Defensins are thought to kill microbes by permeabilizing their plasma membrane. Dimer (PubMed:17452329). Interacts with RETN (PubMed:15064728). ADP-ribosylation drastically reduces cytotoxic and antibacterial activities, and enhances IL8 production. Phosphorylation at Tyr-85 has been found in some cancer cell lines, and interferes with ADP-ribosylation. Belongs to the alpha-defensin family.