Download MendeleyBinding partners for the COOH-terminal appendage domains of the GGAs and gamma-adaptin
Lui, W.W., Collins, B.M., Hirst, J., Motley, A., Millar, C., Schu, P., Owen, D.J., Robinson, M.S.(2003) Mol Cell Biol 14: 2385-23898
- PubMed: 12808037
- DOI: https://doi.org/10.1091/mbc.e02-11-0735
- Primary Citation of Related Structures:
1NA8 - PubMed Abstract:
The adaptor appendage domains are believed to act as binding platforms for coated vesicle accessory proteins. Using glutathione S-transferase pulldowns from pig brain cytosol, we find three proteins that can bind to the appendage domains of both the AP-1 gamma subunit and the GGAs: gamma-synergin and two novel proteins, p56 and p200. p56 elicited better antibodies than p200 and was generally more tractable. Although p56 and gamma-synergin bind to both GGA and gamma appendages in vitro, immunofluorescence labeling of nocodazole-treated cells shows that p56 colocalizes with GGAs on TGN46-positive membranes, whereas gamma-synergin colocalizes with AP-1 primarily on a different membrane compartment. Furthermore, in AP-1-deficient cells, p56 remains membrane-associated whereas gamma-synergin becomes cytosolic. Thus, p56 and gamma-synergin show very strong preferences for GGAs and AP-1, respectively, in vivo. However, the GGA and gamma appendages share the same fold as determined by x-ray crystallography, and mutagenesis reveals that the same amino acids contribute to their binding sites. By overexpressing wild-type GGA and gamma appendage domains in cells, we can drive p56 and gamma-synergin, respectively, into the cytosol, suggesting a possible mechanism for selectively disrupting the two pathways.
Organizational Affiliation:
Department of Clinical Biochemistry, Cambridge Institute for Medical Research, University of Cambridge, United Kingdom.
