Abstract
ABSTRACT UNC-104 (KIF1A) is a neuron-specific kinesin-3 which mainly involved in synaptic vesicles rapid axonal transport. While the function of this motor is of critical importance for neuronal viability and plasticity, little is known about how the motor is regulated. In this thesis, I identified a LIN-2 (CASK) binding site on UNC-104 which overlaps with that of SYD-2 (liprin-α) binding domain. Yeast two-hybrid (Y2H) and co-immunoprecipitation (co-IP) assays reveal specific interaction domains between UNC-104/LIN-2, SYD-2/LIN-2 and MAP-1A(microtubule-associate protein 1A)/LIN-2. These in vitro interactions were further confirmed by using in vivo BiFC (bimolecular fluorescence complementation) assay in living C. elegans. UNC-104 motility, as well as transportation rate of UNC-104 specific cargo, SNB-1 cargo, is significantly diminished in LIN-2 knockout (KO) worms, and this effect cannot be compensated by overexpressing UNC-104’s activator protein SYD-2. Moreover, the diminishing effect on UNC-104 motility can’t be further enhanced in LIN-2 KO/SYD-2 KD worm. These data reveal that LIN-2 and SYD-2 both act in the same UNC-104 regulation pathway and both LIN-2 and SYD-2 are essential for orchestration on activating UNC-104. Lastly, MAP-1A mediated UNC-104 transport characteristics depending on LIN-2, suggesting that LIN-2 plays a central role in regulating kinesin-3 UNC-104.