Clathrin-mediated endocytosis and adaptor proteins

Abstract

Macromolecules gain access to the cytoplasm of eukaryotic cells using one of several ways of which clathrin-dependent endocytosis is the most researched. Although the mechanism of clathrin-mediated endocytosis is well understood in general, novel adaptor proteins that play various roles in ensuring specific regulation of the mentioned process are being discovered all the time. This review provides a detailed account of the mechanism of clathrin-mediated internalization of activated G protein-coupled receptors, as well as a description of the major proteins involved in this process.

Keywords: adaptor proteins; clathrin; endocytosis.

Fig. 1

Schematic diagram of clathrin-mediated internalization of a receptor following its activation

Fig. 2

Clathrin molecule (triskelion). Segments of the clathrin heavy chain are indicated. The terminal domain is the N-terminal domain and the C-terminal domains are localized in the center of the molecule. The position of the light chains is shown schematically. Figure adapted from [40]

Fig. 3

Hexagonal clathrin barrel model (7.9Å resolution). Only the heavy chains of clathrin are indicated. Figure adapted from [40]

Fig. 4

Schematic diagram of the AP complexes. All complexes consist of two large subunits, one medium subunit, and a small subunit. Figure adapted from [63]

Fig. 5

Domain organization of auxilin and Hsc70. Numbers indicate the boundaries of various domains. Figure adapted from [85]

Fig. 6

Monomeric clathrin-binding adaptors. Schematic representation of the overall domain structure. Figure adapted from [70]

Fig. 7

Schematic representation of the protein TRIP8b domain organization