UC Irvine

Movement is an essential part of life. On the cellular level, movement of intracellular components is essential for a cell's vitality. Most eukaryotic cells are too large to rely on diffusion for this, and thus depend on motor proteins. Motor proteins maintain eukaryotic cellular organization by actively transporting cargos and controlling positioning of subcellular structures on actin and microtubule networks. My research focuses on kinesins and dynein, the microtubule-walking motors. Together, these molecules move along cytoplasmic microtubule (MT) highways, allowing appropriate cargo positioning and delivery. While single-molecule cytoplasmic motor function is relatively well understood, there are major gaps in mechanistic understanding of kinesin and dynein regulation in cells. My research has detailed two signaling pathways: one likely regulating the kinesin motor Eg5, and the other regulating dynein. Specifically, my results show that the kinase CK2 activates Eg5 in vitro (Chapter 1). However, the role for CK2 in Eg5 regulation in cells is unclear. I also find that the kinase CDK5 along with 14-3-3 and KIAA0528 promote the phosphorylation of the dynein co-factor NudEL, and that this phosphorylation is essential for dynein force adaptation in cells (Chapter 2). Finally, I discuss the lab's most recent work in uncovering the cellular function of dynein force adaptation, and put this work into the context of the current state of the motors field (Chapter 3).