The p97-FAF1 protein complex reveals a common mode of p97 adaptor binding

Caroline A. Ewens, Silvia Panico, Patrik Kloppsteck, Ciaran McKeown, Ima-Obong Ebong, Carol Robinson, Xiaodong Zhang and Paul S. Freemont

The Journal of Biological Chemistry
2014 vol: 289 pp: 12077-12084 doi: 10.1074/jbc.M114.559591


p97, also known as valosin-containing protein, is a versatile participant in the ubiquitin-proteasome system. p97 interacts with a large network of adaptor proteins to process ubiquitylated substrates in different cellular pathways, including endoplasmic reticulum-associated degradation and transcription factor activation. p97 and its adaptor Fas-associated factor-1 (FAF1) both have roles in the ubiquitin-proteasome system during NF-κB activation, although the mechanisms are unknown. FAF1 itself also has emerging roles in other cell-cycle pathways and displays altered expression levels in various cancer cell lines. We have performed a detailed study the p97-FAF1 interaction. We show that FAF1 binds p97 stably and in a stoichiometry of 3 to 6. Cryo-EM analysis of p97-FAF1 yielded a 17 Å reconstruction of the complex with FAF1 above the p97 ring. Characteristics of p97-FAF1 uncovered in this study reveal common features in the interactions of p97, providing mechanistic insight into how p97 mediates diverse functionalities.

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Topics: ATPases, Electron Microscopy (EM), Fas, Isothermal Titration Calorimetry, Protein Cross-linking, FAF1, p97, Proteins, Publications