Metastatic cancer cells sometimes break off from their point of origin and use motile structures composed of polymerized actin to travel elsewhere in the body. An actin-binding protein named palladin is often overexpressed in metastatic cancer cells. Previous research has shown that an actin binding region of palladin (Ig3) causes an increase in actin's polymerization rate. Now we aim to compare the effects on actin polymerization and organization by the Ig3 domain to that of full-length palladin. The Beck Lab hypothesizes that palladin plays a major part in promoting the motility of cancer cells throughout the body by increasing polymerization and coordinating the structure of actin filaments. The focus of our research is to use Total Internal Reflection Fluorescence (TIRF) microscopy to directly observe actin filaments in the process of polymerization. We aim to capture instances of filament organization and crosslinking, which would help us to understand how palladin influences actin filament organization and what structures it regularly organizes filaments into. In comparing the effects of full length palladin to those seen previously with Ig3, we have found significant changes in the rate of polymerization and filament organization, with a potential for instances of crosslinking. Going forward we would like to use image quantification programs to quantify crosslinking between filaments, in order to better define palladin's ability to promote highly branched actin structures. Defining this capability would help us to understand palladin's responsibility in constructing the invasive cellular structures that allow cancerous cells to metastasize.