Novel function of a dynein light chain in actin assembly during clathrin-mediated endocytosis

• Published in: The Journal of cell biology Vol. 216; no. 8; pp. 2565 - 2580
• Main Authors: Farrell, Kristen B, McDonald, Seth, Lamb, Andrew K, Worcester, Colette, Peersen, Olve B, Di Pietro, Santiago M
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 07-08-2017; The Rockefeller University Press
• Subjects: Actin; Actin Capping Proteins - metabolism; Actin Cytoskeleton - metabolism; Actin-Related Protein 2-3 Complex - genetics; Actin-Related Protein 2-3 Complex - metabolism; Actins - metabolism; Capping; Cargo; Chains; Clathrin; Clathrin-Coated Vesicles - metabolism; Crystal structure; Cytoskeletal Proteins - genetics; Cytoskeletal Proteins - metabolism; Cytoskeleton; Dynein; Dyneins - chemistry; Dyneins - metabolism; Electron Transport Chain Complex Proteins - genetics; Electron Transport Chain Complex Proteins - metabolism; Endocytosis; Eukaryotes; Genotype; Internalization; Kinetics; Machinery and equipment; Microscopy, Fluorescence; Microscopy, Video; Microtubules; Models, Molecular; Motor task performance; Mutation; Phenotype; Polyproline; Protein Binding; Protein Conformation; Proteins; Recruitment; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - chemistry; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Signal Transduction; Structure-Activity Relationship; Yeast
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.201604123

Clathrin- and actin-mediated endocytosis is essential in eukaryotic cells. In this study, we demonstrate that Tda2 is a novel protein of the endocytic machinery necessary for normal internalization of native cargo in yeast. Tda2 has not been classified in any protein family. Unexpectedly, solving the crystal structure of Tda2 revealed it belongs to the dynein light chain family. However, Tda2 works independently of the dynein motor complex and microtubules. Tda2 forms a tight complex with the polyproline motif-rich protein Aim21, which interacts physically with the SH3 domain of the Arp2/3 complex regulator Bbc1. The Tda2-Aim21 complex localizes to endocytic sites in a Bbc1- and filamentous actin-dependent manner. Importantly, the Tda2-Aim21 complex interacts directly with and facilitates the recruitment of actin-capping protein, revealing barbed-end filament capping at endocytic sites to be a regulated event. Thus, we have uncovered a new layer of regulation of the actin cytoskeleton by a member of a conserved protein family that has not been previously associated with a function in endocytosis.