Extended Impact of Pin1 Catalytic Loop Phosphorylation Revealed by S71E Phosphomimetic. Issue 5 (2nd March 2018)

• Record Type: Journal Article
• Authors: Mahoney, Brendan J.; Zhang, Meiling; Zintsmaster, John S.; Peng, Jeffrey W.
• Is Part Of: Journal of molecular biology. Volume 430:Issue 5(2018)
• Page Start: 710
• Page End: 721
• Publication Date: 2018-03-02
• Subjects: MD molecular dynamics -- HSQC heteronuclear single-quantum coherence -- PPIase peptidyl-prolyl isomerase -- EXSY exchange spectroscopy -- CSPs chemical shift perturbations; allostery -- electrostatics -- dynamics -- NMR -- MD; Molecular biology -- Periodicals; Biology -- Periodicals; Biochemistry -- Periodicals; Bacteriology -- Periodicals; Molecular Biology -- Periodicals; Biochemistry -- Periodicals; Biologie moléculaire -- Périodiques; Biologie -- Périodiques; Biochimie -- Périodiques; Moleculaire biologie; Biochemistry; Biology; Molecular biology; Periodicals; 572.805
• DOI: 10.1016/j.jmb.2017.12.021
• Languages: English
• ISSNs: 0022-2836

Abstract

Abstract: Pin1 is a two-domain human protein that catalyzes the cis–trans isomerization of phospho-Ser/Thr–Pro (pS/T–P) motifs in numerous cell-cycle regulatory proteins. These pS/T–P motifs bind to Pin1's peptidyl-prolyl isomerase (PPIase) domain in a catalytic pocket, between an extended catalytic loop and the PPIase domain core. Previous studies showed that post-translational phosphorylation of S71 in the catalytic loop decreases substrate binding affinity and isomerase activity. To define the origins for these effects, we investigated a phosphomimetic Pin1 mutant, S71E-Pin1, using solution NMR. We find that S71E perturbs not only its host loop but also the nearby PPIase core. The perturbations identify a local network of hydrogen bonds and salt bridges that is more extended than previously thought, and includes interactions between the catalytic loop and the α2/α3 turn in the PPIase core. Explicit-solvent molecular dynamics simulations and phylogenetic analysis suggest that these interactions act as conserved "latches" between the loop and PPIase core that enhance binding of phosphorylated substrates, as they are absent in PPIases lacking pS/T–P specificity. Our results suggest that S71 is a hub residue within an electrostatic network primed for phosphorylation, and may illustrate a common mechanism of phosphorylation-mediated allostery. Graphical abstract: Image 1 Highlights: Mechanisms employed by phosphorylation in signaling proteins are not always apparent. Pin1 catalytic loop phosphorylation shows unexpected propagated effects. Combination of NMR and MD unveils a conserved electrostatic network. Evolutionarily primed sites are poised to respond to post-translational modification.