Abstract: Autophagy and apoptosis are essential cellular processes responsible for maintaining cellular and organismal homeostasis. The formation of autophagy-related organelles and apoptosomes is driven by actin polymerization mediated by two pivotal actin regulators, WHAMM and JMY. Both proteins belong to the Wiskott-Aldrich Syndrome protein (WASP) family of actin nucleation promoting factors, containing a C-terminal VCA domain that binds to and activates the Arp2/3 complex to promote actin polymerization. While many of the cellular roles of WHAMM and JMY have been well studied in vivo, the basal state and regulation of both proteins has remained unclear. My project addresses these critical questions by using recombinantly purified proteins and combining biochemical and structural approaches. The insights into how these proteins are regulated can contribute to our understanding of the deregulation of autophagy and apoptosis in cancer.