Molecular Basis for an Ancient Partnership between Prolyl Isomerase Pin1 and Phosphatase Inhibitor-2. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Biochemistry Année : 2011

Molecular Basis for an Ancient Partnership between Prolyl Isomerase Pin1 and Phosphatase Inhibitor-2.

Résumé

Pin1 is a prolyl isomerase that recognizes phosphorylated Ser/Thr-Pro sites, and phosphatase inhibitor-2 (I-2) is phosphorylated during mitosis at a PSpTP site that is expected to be a Pin1 substrate. However, we previously discovered I-2, but not phospho-I-2, bound to Pin1 as an allosteric modifier of Pin1 substrate specificity [Li, M., et al. (2008) Biochemistry 47, 292]. Here, we use binding assays and NMR spectroscopy to map the interactions on Pin1 and I-2 to elucidate the organization of this complex. Despite having sequences that are ∼50% identical, human, Xenopus, and Drosophila I-2 proteins all exhibited identical, saturable binding to GST-Pin1 with K(0.5) values of 0.3 μM. The (1)H-(15)N heteronuclear single-quantum coherence spectra for both the WW domain and isomerase domain of Pin1 showed distinctive shifts upon addition of I-2. Conversely, as shown by NMR spectroscopy, specific regions of I-2 were affected by addition of Pin1. A single-residue I68A substitution in I-2 weakened binding to Pin1 by half and essentially eliminated binding to the isolated WW domain. On the other hand, truncation of I-2 to residue 152 had a minimal effect on binding to the WW domain but eliminated binding to the isomerase domain. Size exclusion chromatography revealed that wild-type I-2 and Pin1 formed a large (>300 kDa) complex and I-2(I68A) formed a complex of half the size that we propose are a heterotetramer and a heterodimer, respectively. Pin1 and I-2 are conserved among eukaryotes from yeast to humans, and we propose they make up an ancient partnership that provides a means for regulating Pin1 specificity and function.

Dates et versions

hal-00618273 , version 1 (01-09-2011)

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Furqan Sami, Caroline Smet-Nocca, Meera Khan, Isabelle Landrieu, Guy Lippens, et al.. Molecular Basis for an Ancient Partnership between Prolyl Isomerase Pin1 and Phosphatase Inhibitor-2.. Biochemistry, 2011, 50 (30), pp.6567-78. ⟨10.1021/bi200553e⟩. ⟨hal-00618273⟩

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