Blood vessels carry oxygen and nutrients and are vital to organismic viability and continued homeostasis.
Angiogenesis, or the formation of new blood vessels from pre-existing ones, is the predominant developmental
process by which blood vessel network density is regulated. During angiogenic development, endothelial cells
create a hollow cavity called a lumen, providing a continuous conduit for blood to reach distant tissues. The
mechanisms underpinning the morphodynamic changes in endothelial architecture and signaling leading to
vascular lumen formation, or tubulogenesis, are incompletely understood. In this proposal we will investigate a
protein called synaptotagmin-like protein 2 (sytl2) that we believe is responsible for de¿ning the luminal surface
by directing protein transport to the apical membrane during blood vessel development. Our preliminary data
suggests that sytl2 de¿nes the apical membrane and tethers Rab GTPase proteins for delivery of vesicular
cargo, such as podocalyxin. In aim 1, we will characterize the role of sytl2a during vascular lumen formation in
developing zebra¿sh embryos using a combination of live-imaging and CRISPR-based mutant generation. In
aim 2, we will comprehensively demonstrate that sylt2 works in combination with the GTPase Rab35 to deliver
podocalyxin to the apical plasma membrane during lumenogenesis in vitro. In aim 3, we will further
characterized how sytl2a interacts with Rab35 to deliver Podocalyxin using generation of new zebra¿sh
reporter lines and compound mutants in vivo. How blood vessel lumen formation is regulated is still a major
question in the ¿eld, this proposal will provide novel insight into critical mechanisms orchestrating this process.