Conférence de l’Institut Jacques Monod – Jordan Raff

Invité par l’Institut Jacques Monod, Prof Jordan Raff, (Sir William Dunn School of Pathology, University of Oxford) présentera une conférence de l’Institut Jacques Monod :

How do cells build complicated organelles?

Résumé:

A key feature of all living things is their ability to assemble complicated structures using dilute building blocks present in the cell. How cells achieve this remarkable feat of bioengineering is largely unknown. Centrosomes are major microtubule (MT) organising centres and important signalling hubs in many cells. They are an excellent model for studying organelle biogenesis as they comprise 10s-100s of copies of several hundred different types of protein yet, like the DNA, they precisely duplicate once per cell cycle. We have recently reconstituted centrosome duplication on synthetic beads programmed to recruit core centrosome assembly proteins when injected into Drosophila embryos. These beads generate structures that appear to be functionally indistinguishable from centrosomes: they recruit centriole/centrosome proteins, organise MTs and proceed through multiple rounds of high-fidelity duplication, all in synchrony with the endogenous centrosomes. The beads function as seeds that recruit biogenesis-promoting proteins to stimulate the assembly of relatively simple scaffolds that direct centrosome self-assembly. This “Seed—Scaffold—Self-Assemble” mechanism may represent a general principle of organelle biogenesis, explaining how simple molecular inputs can generate complex structures without the need to copy a pre-existing template.