Rabbit Anti-Human ANXA2 Polyclonal antibody

The gastrointestinal epithelium functions as an important barrier that separates luminal contents from the underlying tissue compartment and is vital in maintaining mucosal homeostasis. Mucosal wounds in inflammatory disorders compromise the critical epithelial barrier. In response to injury, intestinal epithelial cells (IECs) rapidly migrate to reseal wounds. We have previously observed that a membrane-associated, actin binding protein, annexin A2 (AnxA2), is up-regulated in migrating IECs and plays an important role in promoting wound closure. To identify the mechanisms by which AnxA2 promotes IEC movement and wound closure, we used a loss of function approach. AnxA2-specific shRNA was utilized to generate IECs with stable down-regulation of AnxA2. Loss of AnxA2 inhibited IEC migration while promoting enhanced cell-matrix adhesion. These functional effects were associated with increased levels of beta 1 integrin protein, which is reported to play an important role in mediating the cell-matrix adhesive properties of epithelial cells. Because cell migration requires dynamic turnover of integrin-based adhesions, we tested whether AnxA2 modulates internalization of cell surface beta 1 integrin required for forward cell movement. Indeed, pulse-chase biotinylation experiments in IECs lacking AnxA2 demonstrated a significant increase in cell surface beta 1 integrin that was accompanied by decreased beta 1 integrin internalization and degradation. These findings support an important role of AnxA2 in controlling dynamics of beta 1 integrin at the cell surface that in turn is required for the active turnover of cell-matrix associations, cell migration, and wound closure.

Annexins (ANXs) constitute it family of Ca2+-dependent membrane-binding proteins; at least 20 of them have been described to date. Among these, Annexin A2 (ANXA2) has been revealed as a multi-functional protein in vitro. Its actual role in vivo, however, requires further investigation. We already reported that ANX-I (ANXA1) was Up-regulated in hepatocellular carcinoma (HCC). The role of ANXA2 in various liver diseases including HCC remains obscure. In the present study, the protein and mRNA levels of ANXA2, as well as its localization, were determined for the normal human liver, chronic hepatitis liver, and non-tumorous and tumorous portions of HCC tissues. ANXA2 was rarely detected in either normal or chronic hepatitis liver tissues, whereas it was overexpressed at both the transcriptional and translational levels in tumorous and non-tumorous regions of HCC. In addition, in many cases, more ANXA2 was expressed in the tumorous portion than in the non-tumorous portion of HCC. The expression of ANXA2 was mainly localized in cancer cells, especially in poorly differentiated HCC. Furthermore, ANXA2 was tyrosine-phosphorylated in HCC. These data suggest that overexpression and tyrosine phosphorylation of ANXA2 play important roles in the malignant transformation process leading to HCC and are related to the histological grade of HCC.