DEAN'S SPEAKER SEMINAR: How Cells Build Dynamic Organizers: Centriolar Satellites in Health and Disease

Guest : Dr. Elif Nur Fırat Karalar

Title : How Cells Build Dynamic Organizers: Centriolar Satellites in Health and Disease

Date / Time : 22 Aprıl, Wednesday, 13:40

Location : FENS G025

Abstract: Cells rely on specialized internal organizers to coordinate division, signaling, and responses to their environment. Among these are centriolar satellites, small and dynamic membrane-less assemblies that cluster around the centrosome and primary cilium. Although centriolar satellites have been known for many years, the principles underlying how they form, how they are organized, and how they carry out their functions have remained poorly understood.

In this talk, I will present our recent work showing that centriolar satellites assemble through an ordered hierarchical pathway, beginning with formation of the scaffold protein PCM1 and followed by sequential recruitment of other satellite components. Using new cellular and in vitro biogenesis assays, we further show that PCM1 forms granules through multimerization and phase separation, and that these material properties are regulated by cytoskeletal factors and proteins linked to human ciliopathies. We also find that centriolar satellites are internally organized into subdomains with distinct composition and dynamics, providing a new framework for understanding how membrane-less organelles generate functional complexity. Importantly, perturbing satellite granule properties disrupts ciliary signaling and cell division, directly linking their biophysical organization to biological function.

Together, these findings identify centriolar satellites as key regulators of centrosome and cilium biology, provide insight into how their disruption may contribute to developmental and neurological disease, and offer broader principles for understanding how membrane-less organelles achieve specificity and adaptability in cells.

Bio: Dr. Elif Nur Fırat Karalar is an Associate Professor in the Department of Molecular Biology and Genetics and the School of Medicine at Koç University, where she leads the Cytoskeleton Research Laboratory. Since 2025, she is also the Director of the Sponsored Research Office in the Vice Presidency for Research and Innovation at Koç University.  She received her PhD from the University of California, Berkeley, and completed her postdoctoral training at Stanford University. Since establishing her lab at Koç University in 2014, her research has focused on the centrosome, cilium, and centriolar satellites, with the goal of understanding how defects in these structures contribute to developmental and neurological diseases. Her work has been supported by major national and international funding, including two ERC grants, and recognized by awards such as the EMBO Young Investigator Award, EMBO Membership and the TÜBİTAK Incentive Award.