Structural basis for the accessory protein recruitment by the gamma-adaptin ear domain.
Nogi T,
Shiba Y,
Kawasaki M,
Shiba T,
Matsugaki N,
Igarashi N,
Suzuki M,
Kato R,
Takatsu H,
Nakayama K,
Wakatsuki S.
Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan.
The adaptor proteins AP-1 and GGA regulate membrane traffic between the trans-Golgi network (TGN) and endosomes/lysosomes through ARF-regulated membrane association, recognition of sorting signals, and recruitment of clathrin and accessory proteins. The gamma 1-adaptin subunits of AP-1 and GGA possess homologous ear domains involved in the recruitment of accessory proteins, gamma-synergin and Rabaptin-5. The crystal structure of the human gamma 1-adaptin ear domain consists solely of an immunoglobulin-like fold, unlike the alpha-adaptin ear domain. Structure-based mutational analyses reveal a binding site for the accessory proteins that is composed of conserved basic residues, indicating that the recruitment mechanism in gamma 1-adaptin and GGA is distinct from that in alpha-adaptin.
PMID: 12042876 [PubMed - indexed for MEDLINE]