Annexin A2 expression during cellular differentiation in myeloid cell lines.

Annexin A2 is a calcium-dependent, phospholipid-binding protein found on many cell types. It consists of a short hydrophobic tail (Ser(2)-Asn(32)), which dictates its function, and a core domain (Phe(33)-Asp(339)), which is involved in phospholipid binding. Annexin A2 has been implicated in a number of biochemical processes, including cell proliferation, foetal immune tolerance, ion-channel activation, cell-cell interactions and the bridging of membranes. Annexin A2 is reported to be a powerful activator of plasminogen and, therefore, is implicated in many normal and pathological processes such as haemostasis and metastasis. Myeloid cell lines are used, extensively, to study many aspects of cellular proliferation, differentiation and function. In the present study, we have used flow cytometry and real-time PCR to investigate the role of annexin A2 expression in the proliferation and differentiation of a number of myeloid cell lines. The results demonstrated that annexin A2 expression was affected when the cells were induced to differentiate by stimulation with all-trans-retinoic acid. Annexin A2 may, therefore, be an important player in cellular differentiation and its disorders.