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Séminaire impromptu - Alexandre GrassartEngineering the Genome of Human Cell lines to Study the Dynamics of Endocytosis Pathways.

Abstract :

In mammalian cells, different endocytosis portals have been identified. The diversity of endocytic pathways into the cells offers the required plasticity to finely control the internalization of a wide variety of cargo but also to tightly regulate lipid homeostasis, cell signaling, cell migration or membrane repair. Interestingly, endocytosis pathways differ in many aspects but several factors, such as dynamin2 and actin, are commonly required in multiple routes.

Unfortunately, little is known regarding the conservation of their recruitment, dynamics and functions within the endocytosis system. To date, the investigation of the endocytic machinery in living cells has mostly relied on the over-expression of wild type or dominant-negative mutant proteins.
Although these techniques have provided a tremendous amount of knowledge, such methodology distorted the molecular stoichiometry and may give interaction and/or recruitment of proteins that are normally non-existent due to low interaction. Recently, capacities to efficiently and precisely tailor the human genome opened new avenues to answer these problems. 

In this seminar, I will discuss about these nascent technologies and present the benefits of their application to understand the molecular dynamics of clathrin-mediated endocytosis, caveolae and clathrin-caveolin independent pathways.

Selected publications

Michelot A, Grassart A, Okreglak V, Costanzo M, Boone C, Drubin DG (2013) Actin filament elongation in Arp2/3-derived networks is controlled by three distinct mechanisms. Dev Cell 24:182-195.

Cheng J, Grassart A, Drubin DG (2012) Myosin 1E coordinates actin assembly and cargo trafficking during clathrin-mediated endocytosis. Mol Biol Cell 23:2891-2904.

Grassart A, Meas-Yedid V, Dufour A, Olivo-Marin JC, Dautry-Varsat A, Sauvonnet N (2010) Pak1 phosphorylation enhances cortactin-N-WASP interaction in clathrin-caveolin-independent endocytosis. Traffic 11:1079-1091.