TY - JOUR T1 - Involvement of Annexin A2 in Serum-MAF Dependent Phagocytic Activation of Macrophages JF - Anticancer Research JO - Anticancer Res SP - 4089 LP - 4092 DO - 10.21873/anticanres.15211 VL - 41 IS - 8 AU - KUMPEI KAWAKATSU AU - MISATO MAEMURA AU - YOSHIKA SETA AU - TAKAHITO NISHIKATA Y1 - 2021/08/01 UR - http://ar.iiarjournals.org/content/41/8/4089.abstract N2 - Background/Aim: Serum-derived macrophage activating factor (serum-MAF) is expected to have adjuvant effects through rapid phagocytic activation, which depends on F-actin accumulation in multi-layered membrane ruffles induced within 5 min after serum-MAF addition. This study aimed to elucidate the importance of annexin A2, which is a multifunctional Ca2+-binding protein related to cytoskeletal membrane dynamics, in serum-MAF signalling. Materials and Methods: Annexin A2 and F-actin localizations were analyzed via immunostaining and confocal microscopy. Using EGTA as chelator, the role of Ca2+ in serum-MAF signalling was examined. Results: Annexin A2 was found to translocate from the cytosol to the cell cortex within 30 s of serum-MAF stimulation. Ca2+ chelation inhibited the translocation of annexin A2, frill-like structure formation, and phagocytic activation by serum-MAF. Conclusion: Annexin A2 and Ca2+ were responsible for the rapid phagocytic activation by serum-MAF. This study provides an understanding of phagocytic activation in macrophages, which could be beneficial for cancer immunotherapy. ER -