Mechanical activity of cells and the stress imposed on them by extracellular environment is a constant source of injury to the plasma membrane (PM). In invasive
tumor cells, increased motility together with the harsh environment of the
tumor stroma further increases the risk of PM injury. The impact of these stresses on
tumor cell plasma membrane and mechanism by which
tumor cells repair the PM damage are poorly understood. Ca(2+) entry through the injured PM initiates repair of the PM. Depending on the cell type, different organelles and
proteins respond to this Ca(2+) entry and facilitate repair of the damaged plasma membrane. We recently identified that
proteins expressed in various metastatic
cancers including Ca(2+)-binding EF hand
protein S100A11 and its binding partner
annexin A2 are used by
tumor cells for plasma membrane repair (PMR). Here we will discuss the involvement of S100,
annexin proteins and their regulation of actin cytoskeleton, leading to PMR. Additionally, we will show that another S100 member--S100A4 accumulates at the injured PM. These findings reveal a new role for the S100 and
annexin protein up regulation in metastatic
cancers and identify these
proteins and PMR as targets for treating metastatic
cancers.