The phosphorylation of palladin and the effect on its interaction with actin binding, bundling, and polymerization
Metastatic cell motility, namely breast cancer, has been shown to be regulated in part by the protein palladin. Palladin is a recently described actin binding and bundling protein whose expression level is related to metastatic cancer cell motility. Palladin plays a role in the regulation of actin, a highly abundant protein within a cell, which acts as a cell’s skeleton. Actin is also the structural basis of invasive cellular structures known as invadopodia, which cross the extracellular matrix and allow cells to invade surrounding tissue structures. Palladin has been shown to regulate actin bundles within these invasive structures. Further studies have shown that Akt1, a prominent and highly studied protein kinase, phosphorylates palladin at a linker region between its immunoglobulin domains that are critical for actin bundling. Our work builds upon initial cell-based assays which show that normal cell function is altered when phosphorylation of palladin is misregulated. We utilized biochemical assays to quantify how phosphorylation of palladin affects the structure and function of actin to further understand both of their roles in cancer cell motility.