Project Summary:
The Primary cilium is an organelle that majority of human cells possess with only one per a cell.
This immotile cellular structure senses extracellular signaling via receptors that specifically
accumulate on the ciliary portion of the cellular membrane. Dysfunction in the structure or the
function of the organelle results in pleiotropic disorders called ciliopathies, which include
obesity and retinal degeneration. The cilium needs to be disassembled prior to mitosis, as cells
use centrosome, from which the cilium extends, as spindle poles. Cells reassemble the cilium in
G0/G1 phase of the cell cycle. My lab at University of Oklahoma Health Science Center
interrogates the molecular mechanisms of the formation of the cilium. The initial step of the
cilium formation is recruitment of a ciliary vesicle, to the distal end of the mother centriole. The
small vesicles fuse to form a larger vesicle, which finally merges with plasma membrane to form
the primary cilium. While the attachment of the ciliary vesicle to the centriole is the first step,
many important questions remain to be elucidated. One potential problem that has hampered
our understanding of the ciliary vesicle is the lack of markers of the ciliary vesicle. To overcome
this challenge, I previously characterized a small GTPase, RAB34, a more specific marker for the
ciliary vesicle, and determined that Neuronal Calcium Sensor-1 (NCS1) captures the ciliary
vesicle using its myristoylation motif at the ciliary base. Using these proteins as powerful
biochemical tools, we will focus on answering key unsolved questions including the composition
and origin of the ciliary vesicle. We will isolate the ciliary vesicle to uncover the lipid and
protein composition of the vesicle, monitor the movement of the ciliary vesicle from its
emergence to reveal the origin of the vesicle, and screen for the regulators that determine how
the vesicle is generated and transported to the centriole. If successful, our research projects
will uncover the largely unexplored molecular mechanisms of the early step of the cilium
formation, which will pave the way to get to the root of the pathogenesis of the syndrome
caused by ciliary dysfunction.