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Structure of a conserved dimerisation domain within Fbox7 and PI31Structure of a conserved dimerisation domain within Fbox7 and PI31
Structural highlights
FunctionPSMF1_HUMAN Plays an important role in control of proteasome function. Inhibits the hydrolysis of protein and peptide substrates by the 20S proteasome. Also inhibits the activation of the proteasome by the proteasome regulatory proteins PA700 and PA28.[1] Evolutionary Conservation![]() Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedF-box proteins are the substrate-recognition components of the Skp1-Cul1-F box protein (SCF) E3 ubiquitin ligases. Here we report a structural relationship between Fbxo7, a component of the SCF(Fbxo7) E3 ligase, and the proteasome inhibitor PI31. SCF(Fbxo7) is known to catalyze the ubiquitination of hepatoma-up-regulated protein (HURP) and the inhibitor of apoptosis (IAP) protein but also functions as an activator of cyclin D-Cdk6 complexes. We identify PI31 as an Fbxo7.Skp1 binding partner and show that this interaction requires an N-terminal domain present in both proteins that we term the FP (Fbxo7/PI31) domain. The crystal structure of the PI31 FP domain reveals a novel alpha/beta-fold. Biophysical and mutational analyses are used to map regions of the PI31 FP domain mediating homodimerization and required for heterodimerization with Fbxo7.Skp1. Equivalent mutations in Fbxo7 ablate interaction with PI31 and also block Fbxo7 homodimerization. Knockdown of Fbxo7 does not affect PI31 levels arguing against PI31 being a substrate for SCF(Fbxo7). We present a model for FP domain-mediated dimerization of SCF(Fbxo7) and PI31. Structure of a conserved dimerization domain within the F-box protein Fbxo7 and the PI31 proteasome inhibitor.,Kirk R, Laman H, Knowles PP, Murray-Rust J, Lomonosov M, Meziane el K, McDonald NQ J Biol Chem. 2008 Aug 8;283(32):22325-35. Epub 2008 May 20. PMID:18495667[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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