ENTH and ANTH domain proteins participate in AP2-independent clathrin-mediated endocytosis

Manna, Paul T. and Gadelha, Catarina and Puttick, Amy E. and Field, Mark C. (2015) ENTH and ANTH domain proteins participate in AP2-independent clathrin-mediated endocytosis. Journal of Cell Science, 128 (11). pp. 2130-2142. ISSN 1477-9137

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Clathrin-mediated endocytosis (CME) is a major route of entry into eukaryotic cells. A core of evolutionarily ancient genes encodes many components of this system but much of our mechanistic understanding of CME is derived from a phylogenetically narrow sampling of a few model organisms. In the parasite Trypanosoma brucei, which is distantly related to the better characterised animals and fungi, exceptionally fast endocytic turnover aids its evasion of the host immune system. Although clathrin is absolutely essential for this process, the adaptor protein complex 2 (AP2) has been secondarily lost, suggesting mechanistic divergence. Here, we characterise two phosphoinositide-binding monomeric clathrin adaptors, T. brucei (Tb)EpsinR and TbCALM, which in trypanosomes are represented by single genes, unlike the expansions present in animals and fungi. Depletion of these gene products reveals essential, but partially redundant, activities in CME. Ultrastructural analysis of TbCALM and TbEpsinR double-knockdown cells demonstrated severe defects to clathrin-coated pit formation and morphology associated with a dramatic inhibition of endocytosis. Depletion of TbCALM alone, however, produced a distinct lysosomal segregation phenotype, indicating an additional non-redundant role for this protein. Therefore, TbEpsinR and TbCALM represent ancient phosphoinositide-binding proteins with distinct and vital roles in AP2-independent endocytosis.

Item Type: Article
Schools/Departments: University of Nottingham UK Campus > Faculty of Medicine and Health Sciences > School of Life Sciences
Identification Number: https://doi.org/10.1242/jcs.167726
Depositing User: Gadelha, Catarina
Date Deposited: 25 Jul 2016 12:10
Last Modified: 24 Sep 2016 04:49
URI: http://eprints.nottingham.ac.uk/id/eprint/35362

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