ESR2

The role of actin dynamics in photoreceptor sensory cilium development and homeostasis


The relationship of actin and the cilium is a complex one. F-actin depolymerization can promote ciliogenesis and cilium elongation, but also results in cilia shortening or deciliation. We discovered that a WASF3-ARP2/3 axis drives ciliary membrane evaginations in photoreceptor sensory cilia, initiating the formation of the stacked, opsin-filled membrane discs that allow phototransduction, but the details of which are not known. Defects in this process leads to inherited retinal degeneration (IRD). ESR2 will use optimized CRISPR/Cas9-based genome editing of isogenic hiPSC lines to tag endogenous retinal ciliopathy-associated proteins suspected to participate in this process (SPATA7/RPGRIP1, INPP5E/TULP3, BBS4/6), with epitopes optimized for STORM superresolution localization (mNeonGreen and mScarlet), live cell proteomics by proximity labelling (TurboID/MS, in collaboration with P7-EKUT), and live cell imaging (mNeonGreen-Lifeact). ESR2 will deploy these procedures at different timepoints of differentiation into photoreceptor precursors and organoids to establish the dynamics of the actin assembly process during the first stages of photoreceptor cilium development, and its loss in IRD by evaluating isogenic patient vs control lines.

Partner: Radboud University Medical Centre Nijmegen, The Netherlands

Supervisor: prof dr ir. R. Roepman