@article{1624365,

title = {The structural basis of PTEN regulation by multi-site phosphorylation},

author = {D. R. Dempsey and T. Viennet and R. Iwase and E. Y. Park and S. Henriquez and Z. Chen and J. R. Jeliazkov and B. A. Palanski and K. L. Phan and P. Coote and J. J. Gray and M. J. Eck and S. B. Gabelli and H. Arthanari and P. A. Cole},

doi = {10.1038/s41594-021-00668-5},

issn = {1545-9985},

year  = {2021},

date = {2021-10-28},

urldate = {2021-10-28},

journal = {Nat. Struct. Mol. Biol.},

volume = {28},

number = {10},

pages = {858-868},

abstract = {Phosphatase and tensin homolog (PTEN) is a phosphatidylinositol-3,4,5-triphosphate (PIP3) phospholipid phosphatase that is commonly mutated or silenced in cancer. PTEN’s catalytic activity, cellular membrane localization and stability are orchestrated by a cluster of C-terminal phosphorylation (phospho-C-tail) events on Ser380, Thr382, Thr383 and Ser385, but the molecular details of this multi-faceted regulation have remained uncertain. Here we use a combination of protein semisynthesis, biochemical analysis, NMR, X-ray crystallography and computational simulations on human PTEN and its sea squirt homolog, VSP, to obtain a detailed picture of how the phospho-C-tail forms a belt around the C2 and phosphatase domains of PTEN. We also visualize a previously proposed dynamic N-terminal α-helix and show that it is key for PTEN catalysis but disordered upon phospho-C-tail interaction. This structural model provides a comprehensive framework for how C-tail phosphorylation can impact PTEN’s cellular functions.},

keywords = {Animals, Ciona intestinalis, Crystallography, Fluorescence Polarization, Humans, Magnetic Resonance Spectroscopy, Molecular Docking Simulation, Phosphorylation, PTEN Phosphohydrolase, X-Ray},

pubstate = {published},

tppubtype = {article}

}

@article{1299940,

title = {Investigation of N-Terminal Phospho-Regulation of~Uracil DNA Glycosylase Using Protein Semisynthesis},

author = {Brian P Weiser and James T Stivers and Philip A Cole},

doi = {10.1016/j.bpj.2017.06.016},

issn = {1542-0086},

year  = {2017},

date = {2017-07-01},

journal = {Biophys J},

volume = {113},

number = {2},

pages = {393-401},

abstract = {Uracil DNA Glycosylase (UNG2) is the primary enzyme in humans that prevents the stable incorporation of deoxyuridine monophosphate into DNA in the form of U/A basepairs. During S-phase, UNG2 remains associated with the replication fork through its interactions with two proteins, Proliferating Cell Nuclear Antigen (PCNA) and Replication Protein A (RPA), which are critical for DNA replication and repair. In this work, we used protein semisynthesis and fluorescence anisotropy assays to explore the interactions of UNG2 with PCNA and RPA and to determine the effects of two UNG2 phosphorylation sites (Thr6 and Tyr8) located within its PCNA-interacting motif (PIP-box). In binding assays, we found that phosphorylation of Thr6 or Tyr8 on UNG2 can impede PCNA binding without affecting UNG2 catalytic activity or its RPA interaction. Our data also suggests that unmodified UNG2, PCNA, and RPA can form a ternary protein complex. We propose that the UNG2 N-terminus may serve as a flexible scaffold to tether PCNA and RPA at the replication fork, and that post-translational modifications on the UNG2 N-terminus disrupt formation of the PCNA-UNG2-RPA protein complex.},

keywords = {Catalysis, DNA Glycosylases, Electrospray Ionization, Escherichia coli, Humans, Mass, Mutation, Phosphorylation, Proliferating Cell Nuclear Antigen, Protein Binding, Protein Domains, Protein Stability, Replication Protein A, Spectrometry},

pubstate = {published},

tppubtype = {article}

}

@article{1299944,

title = {A Tunable Brake for HECT Ubiquitin Ligases},

author = {Zan Chen and Hanjie Jiang and Wei Xu and Xiaoguang Li and Daniel R Dempsey and Xiangbin Zhang and Peter Devreotes and Cynthia Wolberger and L Mario Amzel and Sandra B Gabelli and Philip A Cole},

doi = {10.1016/j.molcel.2017.03.020},

issn = {1097-4164},

year  = {2017},

date = {2017-05-01},

journal = {Mol Cell},

volume = {66},

number = {3},

pages = {345-357.e6},

abstract = {The HECT E3 ligases ubiquitinate numerous transcription factors and signaling molecules, and their activity must be tightly controlled to prevent cancer, immune disorders, and other diseases. In this study, we have found unexpectedly that peptide linkers tethering WW domains in several HECT family members are key regulatory elements of their catalytic activities. Biochemical, structural, and cellular analyses have revealed that the linkers can lock the HECT domain in an inactive conformation and block the proposed allosteric ubiquitin binding site. Such linker-mediated autoinhibition of the HECT domain can be relieved by linker post-translational modifications, but complete removal of the brake can induce hyperactive autoubiquitination and E3 self destruction. These results clarify the mechanisms of several HECT protein cancer associated mutations and provide a new framework for understanding how HECT ubiquitin ligases must be finely tuned to ensure normal cellular behavior.},

keywords = {Allosteric Regulation, Endosomal Sorting Complexes Required for Transport, Enzyme Activation, Enzyme Stability, HeLa Cells, Humans, Models, Molecular, Mutation, Nedd4 Ubiquitin Protein Ligases, Phosphorylation, Post-Translational, Protein Domains, Protein Processing, Proteolysis, Repressor Proteins, Structure-Activity Relationship, Transfection, Ubiquitin-Protein Ligases},

pubstate = {published},

tppubtype = {article}

}

@article{1299949,

title = {Enzyme-catalyzed expressed protein ligation},

author = {Samuel H Henager and Nam Chu and Zan Chen and David Bolduc and Daniel R Dempsey and Yousang Hwang and James Wells and Philip A Cole},

doi = {10.1038/nmeth.4004},

issn = {1548-7105},

year  = {2016},

date = {2016-11-01},

journal = {Nat Methods},

volume = {13},

number = {11},

pages = {925-927},

abstract = {Expressed protein ligation is a valuable method for protein semisynthesis that involves the reaction of recombinant protein C-terminal thioesters with N-terminal cysteine (N-Cys)-containing peptides, but the requirement of a Cys residue at the ligation junction can limit the utility of this method. Here we employ subtiligase variants to efficiently ligate Cys-free peptides to protein thioesters. Using this method, we have more accurately determined the effect of C-terminal phosphorylation on the tumor suppressor protein PTEN.},

keywords = {Animals, Bacillus subtilis, Blotting, Catalytic Domain, Cells, Cultured, Cysteine, Escherichia coli, Fibroblasts, Mice, Mutagenesis, Peptide Fragments, Peptide Synthases, Phosphorylation, Post-Translational, Protein Processing, PTEN Phosphohydrolase, Recombinant Proteins, Site-Directed, Subtilisins, Western},

pubstate = {published},

tppubtype = {article}

}

@article{1299966,

title = {Molecular Features of Phosphatase and Tensin Homolog (PTEN) Regulation by C-terminal Phosphorylation},

author = {Zan Chen and Daniel R Dempsey and Stefani N Thomas and Dawn Hayward and David M Bolduc and Philip A Cole},

doi = {10.1074/jbc.M116.728980},

issn = {1083-351X},

year  = {2016},

date = {2016-07-01},

journal = {J Biol Chem},

volume = {291},

number = {27},

pages = {14160-9},

abstract = {PTEN is a tumor suppressor that functions to negatively regulate the PI3K/AKT pathway as the lipid phosphatase for phosphatidylinositol 3,4,5-triphosphate. Phosphorylation of a cluster of Ser/Thr residues (amino acids 380-385) on the C-terminal tail serves to alter the conformational state of PTEN from an open active state to a closed inhibited state, resulting in a reduction of plasma membrane localization and inhibition of enzyme activity. The relative contribution of each phosphorylation site to PTEN autoinhibition and the structural basis for the conformational closure is still unclear. To further the structural understanding of PTEN regulation by C-terminal tail phosphorylation, we used protein semisynthesis to insert stoichiometric and site-specific phospho-Ser/Thr(s) in the C-terminal tail of PTEN. Additionally, we employed photo-cross-linking to map the intramolecular PTEN interactions of the phospho-tail. Systematic evaluation of the PTEN C-tail phospho-cluster showed autoinhibition, and conformational closure was influenced by the aggregate effect of multiple phospho-sites rather than dominated by a single phosphorylation site. Moreover, photo-cross-linking suggested a direct interaction between the PTEN C-tail and a segment in the N-terminal region of the catalytic domain. Mutagenesis experiments provided additional insights into how the PTEN phospho-tail interacts with both the C2 and catalytic domains.},

keywords = {Amino Acid Sequence, Humans, Phosphorylation, PTEN Phosphohydrolase},

pubstate = {published},

tppubtype = {article}

}

@article{1299971,

title = {Synthetic approaches to protein phosphorylation},

author = {Zan Chen and Philip A Cole},

doi = {10.1016/j.cbpa.2015.07.001},

issn = {1879-0402},

year  = {2015},

date = {2015-10-01},

journal = {Curr Opin Chem Biol},

volume = {28},

pages = {115-22},

abstract = {Reversible protein phosphorylation is critically important in biology and medicine. Hundreds of thousands of sites of protein phosphorylation have been discovered but our understanding of the functions of the vast majority of these post-translational modifications is lacking. This review describes several chemical and biochemical methods that are under development and in current use to install phospho-amino acids and their mimics site-specifically into proteins. The relative merits of total chemical synthesis, semisynthesis, and nonsense suppression strategies for studying protein phosphorylation are discussed in terms of technical simplicity, scope, and versatility.},

keywords = {Animals, Humans, Mutagenesis, Phosphoproteins, Phosphorylation, Protein Transport, Recombinant Proteins, Site-Directed},

pubstate = {published},

tppubtype = {article}

}

@article{1299976,

title = {How IGF-1 activates its receptor},

author = {Jennifer M Kavran and Jacqueline M McCabe and Patrick O Byrne and Mary Katherine Connacher and Zhihong Wang and Alexander Ramek and Sarvenaz Sarabipour and Yibing Shan and David E Shaw and Kalina Hristova and Philip A Cole and Daniel J Leahy},

doi = {10.7554/eLife.03772},

issn = {2050-084X},

year  = {2014},

date = {2014-09-01},

journal = {Elife},

volume = {3},

abstract = {The type I insulin-like growth factor receptor (IGF1R) is involved in growth and survival of normal and neoplastic cells. A ligand-dependent conformational change is thought to regulate IGF1R activity, but the nature of this change is unclear. We point out an underappreciated dimer in the crystal structure of the related Insulin Receptor (IR) with Insulin bound that allows direct comparison with unliganded IR and suggests a mechanism by which ligand regulates IR/IGF1R activity. We test this mechanism in a series of biochemical and biophysical assays and find the IGF1R ectodomain maintains an autoinhibited state in which the TMs are held apart. Ligand binding releases this constraint, allowing TM association and unleashing an intrinsic propensity of the intracellular regions to autophosphorylate. Enzymatic studies of full-length and kinase-containing fragments show phosphorylated IGF1R is fully active independent of ligand and the extracellular-TM regions. The key step triggered by ligand binding is thus autophosphorylation.},

keywords = {Amino Acid Sequence, Animals, Conserved Sequence, HEK293 Cells, Humans, IGF Type 1, Insulin, Insulin-Like Growth Factor I, Ligands, Mice, Models, Molecular, Molecular Sequence Data, Mutation, Phosphorylation, Protein Binding, Protein Multimerization, Protein Structure, Receptor, Tertiary},

pubstate = {published},

tppubtype = {article}

}

@article{1299974,

title = {Catalytic mechanisms and regulation of protein kinases},

author = {Z. Wang and P. A. Cole},

doi = {10.1016/B978-0-12-397918-6.00001-X},

issn = {1557-7988},

year  = {2014},

date = {2014-00-00},

journal = {Methods Enzymol.},

volume = {548},

pages = {1-21},

abstract = {Protein kinases transfer a phosphoryl group from ATP onto target proteins and play a critical role in signal transduction and other cellular processes. Here, we review the kinase kinetic and chemical mechanisms and their application in understanding kinase structure and function. Aberrant kinase activity has been implicated in many human diseases, in particular cancer. We highlight applications of technologies and concepts derived from kinase mechanistic studies that have helped illuminate how kinases are regulated and contribute to pathophysiology.},

keywords = {Adenosine Triphosphate, Animals, Biocatalysis, Humans, Models, Molecular, Mutation, Phosphorylation, Post-Translational, Protein Conformation, Protein Kinase Inhibitors, Protein Kinases, Protein Processing, Substrate Specificity},

pubstate = {published},

tppubtype = {article}

}

@article{1299965,

title = {Enzymatic Analysis of PTEN Ubiquitylation by WWP2 and NEDD4-1 E3 Ligases},

author = {Zan Chen and Stefani N Thomas and David M Bolduc and Xuejun Jiang and Xiangbin Zhang and Cynthia Wolberger and Philip A Cole},

doi = {10.1021/acs.biochem.6b00448},

issn = {1520-4995},

journal = {Biochemistry},

volume = {55},

number = {26},

pages = {3658-66},

abstract = {PTEN is a lipid phosphatase that converts phosphatidylinositol 3,4,5-phosphate (PIP3) to phosphatidylinositol 4,5-phosphate (PIP2) and plays a critical role in the regulation of tumor growth. PTEN is subject to regulation by a variety of post-translational modifications, including phosphorylation on a C-terminal cluster of four Ser/Thr residues (380, 382, 383, and 385) and ubiquitylation by various E3 ligases, including NEDD4-1 and WWP2. It has previously been shown that C-terminal phosphorylation of PTEN can increase its cellular half-life. Using in vitro ubiquitin transfer assays, we show that WWP2 is more active than NEDD4-1 in ubiquitylating unphosphorylated PTEN. The mapping of ubiquitylation sites in PTEN by mass spectrometry showed that both NEDD4-1 and WWP2 can target a broad range of Lys residues in PTEN, although NEDD4-1 versus WWP2 showed a stronger preference for ubiquitylating PTEN’s C2 domain. Whereas tetraphosphorylation of PTEN did not significantly affect its ubiquitylation by NEDD4-1, it inhibited PTEN ubiquitylation by WWP2. Single-turnover and pull-down experiments suggested that tetraphosphorylation of PTEN appears to weaken its interaction with WWP2. These studies reveal how the PTEN E3 ligases WWP2 and NEDD4-1 exhibit distinctive properties in Lys selectivity and sensitivity to PTEN phosphorylation. Our findings also provide a molecular mechanism for the connection between PTEN Ser/Thr phosphorylation and PTEN’s cellular stability.},

keywords = {Chromatography, Endosomal Sorting Complexes Required for Transport, Humans, Immunoprecipitation, Liquid, Nedd4 Ubiquitin Protein Ligases, Phosphorylation, Post-Translational, Protein Processing, PTEN Phosphohydrolase, Tandem Mass Spectrometry, Ubiquitin, Ubiquitin-Protein Ligases, Ubiquitination, X-Linked Inhibitor of Apoptosis Protein},

pubstate = {published},

tppubtype = {article}

}