Maturation and exchange in cellular organelles
AbstractCo-authors: Serge Dmitrieff (EMBL), Madan Rao (NCBS)
Most molecules secreted or internalized by Eukaryotic cells follow well defined routes, the secretory and endocytic pathways, along which they are exposed to a succession of biochemical environments by sequentially visiting different membrane-bound organelles. Molecules internalized by endocytosis move from early to late endosomes before being sorted and carried to their final destination. Molecules synthesized in the endoplasmic reticulum go through the Golgi apparatus, itself divided into cis, medial and trans compartments (called cisternae), where they undergo post-transcriptional maturation and sorting. One fundamental issue underlying the organization and regulation of intracellular transport is whether progression along the transport pathways occurs by exchange between organelles of fixed biochemical identities (via the budding and scission of carrier vesicles), or by the biochemical maturation of the organelles themselves. In this talk, I will present some aspects of the Physics of out-of-equilibrium membrane system, and discuss their relevance to intra-cellular transport. I will particularly focus on the dynamical coupling between biochemical maturation and phase separation of membrane components, and its possible relevance for the generation and maintenance of the Golgi apparatus.