<p>Proteins synthesized on the ribosome and processed in the endoplasmic reticulum are transported from the Golgi apparatus to the trans-Golgi network (TGN), and from there via small carrier vesicles to their final destination compartment. These vesicles have specific coat proteins (such as clathrin or coatomer) that are important for cargo selection and direction of transport [<cite idref="PUB00035769"/>]. Clathrin coats contain both clathrin (acts as a scaffold) and adaptor complexes that link clathrin to receptors in coated vesicles. Clathrin-associated protein complexes are believed to interact with the cytoplasmic tails of membrane proteins, leading to their selection and concentration. The two major types of clathrin adaptor complexes are the heterotetrameric adaptor protein (AP) complexes, and the monomeric GGA (Golgi-localising, Gamma-adaptin ear domain homology, ARF-binding proteins) adaptors [<cite idref="PUB00035753"/>, <cite idref="PUB00035765"/>].</p><p> Clathrin is a trimer composed of three heavy chains and three light chains, each monomer projecting outwards like a leg; this three-legged structure is known as a triskelion [<cite idref="PUB00035906"/>, <cite idref="PUB00035907"/>]. The heavy chains form the legs, their N-terminal beta-propeller regions extending outwards, while their C-terminal alpha-alpha-superhelical regions form the central hub of the triskelion. Peptide motifs can bind between the beta-propeller blades. The light chains appear to have a regulatory role, and may help orient the assembly and disassembly of clathrin coats as they interact with hsc70 uncoating ATPase [<cite idref="PUB00035908"/>]. Clathrin triskelia self-polymerise into a curved lattice by twisting individual legs together. The clathrin lattice forms around a vesicle as it buds from the TGN, plasma membrane or endosomes, acting to stabilise the vesicle and facilitate the budding process [<cite idref="PUB00035769"/>]. The multiple blades created when the triskelia polymerise are involved in multiple protein interactions, enabling the recruitment of different cargo adaptors and membrane attachment proteins [<cite idref="PUB00035909"/>]. </p><p>This entry represents the 7-fold alpha-alpha-superhelical ARM-type repeat found at the C-terminal of clathrin heavy chains and in VPS (vacuolar protein sorting-associated) proteins. In clathrin heavy chains, the C-terminal 7-fold ARM-type repeats interact to form the central hub of the triskelion. VPS proteins are required for vacuolar assembly and vacuolar traffick, and contain one clathrin-type repeat [<cite idref="PUB00035770"/>].</p><p>More information about these proteins can be found at Protein of the Month: Clathrin [<cite idref="PUB00035905"/>].</p> Clathrin, heavy chain/VPS, 7-fold repeat