Actin cytoskeleton is essential for eukaryotic cells. To exert its countless cellular functions, actin undergoes dynamic remodeling orchestrated by the large number of actin-interacting factors. Cellular conditions favor actin assembly (polymerization) as opposed to actin disassembly (depolymerization), and our understanding of actin disassembly mechanisms is still incomplete. In this talk I will discuss a unique mechanism of actin disassembly that relies on site- and stereo-specific oxidation/reduction of actin. This enzymatic oxidation is introduced by the Mical family of enzymes, and it primes actin filaments for disassembly. I will discuss how this posttranslational modification synergizes with some of the key actin regulators – cofilin and profilin – to orchestrate actin disassembly independently of its nucleotide-bound state and to suppress its repolymerization.
1. Recognize that oxidation of proteins can be a regulatory mechanism as opposed to oxidative damage.
2. Explain how site-specific oxidation introduced by Mical enzymes synergizes with other regulatory proteins to promote disassembly of actin filaments.