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Current Opinion in Cell Biology Apr 2001Phosphorylation of proteins on serine and threonine residues has traditionally been viewed as a means to allosterically regulate catalytic activity. Research within the... (Review)
Review
Phosphorylation of proteins on serine and threonine residues has traditionally been viewed as a means to allosterically regulate catalytic activity. Research within the past five years, however, has revealed that serine/threonine phosphorylation can also directly result in the formation of multimolecular signaling complexes through specific interactions between phosphoserine/threonine (pSer/Thr)-binding modules and phosphorylated sequence motifs. pSer/Thr-binding proteins and domains currently include 14-3-3, WW domains, forkhead-associated domains, and, tentatively, WD40 repeats and leucine-rich regions. It seems likely that additional modules will be found in the future. The amino acid sequences recognized by these pSer/Thr-binding modules show partial overlap with the optimal phosphorylation motifs for different protein kinase subfamilies, allowing the formation of specific signaling complexes to be controlled through combinatorial interactions between particular upstream kinases and a particular binding module. The structural basis for pSer/Thr binding differs dramatically between 14-3-3 proteins, WW domains and forkhead-associated domains, suggesting that their pSer/Thr binding function was acquired through convergent evolution.
Topics: Animals; Binding Sites; Humans; Phosphoproteins; Phosphorylation; Phosphoserine; Phosphothreonine; Protein Structure, Tertiary
PubMed: 11248545
DOI: 10.1016/s0955-0674(00)00189-7 -
Archives of Biochemistry and Biophysics Feb 2021The effects of phosphorylation of histone H3 at serine 10 have been studied in the context of other posttranslational modifications such as lysine methylation. We set...
The effects of phosphorylation of histone H3 at serine 10 have been studied in the context of other posttranslational modifications such as lysine methylation. We set out to investigate the impact of phosphoserine-10 on arginine-8 methylation. We performed methylation reactions using peptides based on histone H3 that contain a phosphorylated serine and compared the extent of arginine methylation with unmodified peptides. Results obtained via fluorography indicate that peptides containing a phosphorylated serine-10 inhibit deposition of methyl groups to arginine-8 residues. To further explore the effects of phosphoserine on neighboring arginine residues, we physically characterized the non-covalent interactions between histone H3 phosphoserine-10 and arginine-8 using P NMR spectroscopy. A salt bridge was detected between the negatively charged phosphoserine-10 and the positively charged unmodified arginine-8 residue. This salt bridge was not detected when arginine-8 was symmetrically dimethylated. Finally, molecular simulations not only confirm the presence of a salt bridge but also identify a subset of electrostatic interactions present when arginine is replaced with alanine. Taken together, our work suggests that the negatively charged phosphoserine maximizes its interactions. By limiting its exposure and creating new contacts with neighboring residues, it will inhibit deposition of neighboring methyl groups, not through steric hindrance, but by forming intrapeptide interactions that may mask substrate recognition. Our work provides a mechanistic framework for understanding the role of phosphoserine on nearby amino acid residues and arginine methylation.
Topics: Amino Acid Motifs; Amino Acid Sequence; Animals; Arginine; Histones; Humans; Methylation; Molecular Dynamics Simulation; Phosphoserine; Protein Processing, Post-Translational; Static Electricity; Xenopus laevis
PubMed: 33309545
DOI: 10.1016/j.abb.2020.108716 -
Food Chemistry May 2024When subjected to dry-heating, egg white ovalbumin, a phosphoglycoprotein, undergoes fragmentation and forms soluble aggregates. We investigated the mechanisms of...
When subjected to dry-heating, egg white ovalbumin, a phosphoglycoprotein, undergoes fragmentation and forms soluble aggregates. We investigated the mechanisms of dry-heat-induced fragmentation of ovalbumin. SDS-PAGE analysis showed that ovalbumin fragmented into five polypeptides, and their amount increased over 6 h of dry-heat treatment at 120 °C. The fragments contained fewer or no phosphoserine, compared with that in crude ovalbumin. Liquid chromatography-tandem mass spectrometry analysis of tryptic digests revealed that the fragmentation sites were located on phosphoserine residues, S and S. During fragmentation, the phosphoserine residues underwent conversion into dehydroalanine residues, which were subsequently hydrolyzed. The nitrogen from the dehydroalanine became a newly formed terminal amide group on the N-terminal fragment, while the remaining molecule predominantly formed a new terminal pyruvoyl group. Furthermore, the fragments were incorporated into monomers or soluble aggregates of ovalbumin via covalent and non-covalent bonds. This study demonstrated a novel mechanism for dry-heat-induced fragmentation of phosphoproteins.
Topics: Ovalbumin; Phosphoserine; Hot Temperature; Peptides; Egg White
PubMed: 38159316
DOI: 10.1016/j.foodchem.2023.138263 -
Structure (London, England : 1993) Mar 2001The fundamental biological importance of protein phosphorylation is underlined by the existence of more than 500 protein kinase genes within the human genome. In many... (Review)
Review
The fundamental biological importance of protein phosphorylation is underlined by the existence of more than 500 protein kinase genes within the human genome. In many cases, phosphorylation on serine, threonine, and tyrosine residues creates binding surfaces for a variety of phospho-amino acid binding proteins/modules. Here, we review the insights into serine/threonine phosphorylation-dependent signal transduction processes provided by structures of several of these proteins and their complexes.
Topics: Animals; Humans; Models, Molecular; Phosphorylation; Phosphoserine; Phosphothreonine; Protein Binding; Protein Structure, Tertiary; Signal Transduction
PubMed: 11286893
DOI: 10.1016/s0969-2126(01)00580-9 -
Histochemistry and Cell Biology Feb 2023Uterine myocytes during pregnancy proceed through a series of adaptations and collectively transform into a powerfully contractile tissue by term. Previous work has...
Uterine myocytes during pregnancy proceed through a series of adaptations and collectively transform into a powerfully contractile tissue by term. Previous work has indicated that members of the heat shock protein (HSP) B family of stress proteins are associated with the process of adaptation and transformation. Utilizing immunoblot analyses, widefield epifluorescence and total internal reflection (TIRF) microscopy, this study investigated the temporal and spatial detection of HSPB1 phosphorylated on serine-86 (pS86-HSPB1) in rat myometrium during pregnancy, the role of uterine distension in regulation of pS86-HSPB1, and the comparative localization with pS15-HSPB1 in rat myometrial tissue as well as in an immortalized human myometrial cell line. Immunoblot detection of pS86-HSPB1 was significantly elevated during late pregnancy and labour. In particular, pS86-HSPB1 was significantly increased at day (d)22 and d23 (labour) compared with all other timepoints assessed. Localization of pS86-HSPB1 in myometrium became prominent at d22 and d23 with cytoplasmic detection around myometrial cell nuclei. Furthermore, pS86-HSPB1 detection was found to be significantly elevated in the gravid rat uterine myometrium compared with the non-gravid tissue at d19 and d23. Both widefield epifluorescence and TIRF microscopy examination of human myometrial cells demonstrated that pS15-HSPB1 was prominently localized to focal adhesions, while pS82-HSPB1 (homologous to rodent pS86-HSPB1) was primarily located in the cell cytoplasm. Our data demonstrate that levels of phosphorylated HSPB1 increase just prior to and during labour, and that uterine distension is a stress-inducing signal for HSPB1 phosphorylation. The exact roles of these phosphorylated forms in myometrial cells remain to be determined.
Topics: Female; Pregnancy; Rats; Animals; Humans; Myometrium; Phosphoserine; Rats, Sprague-Dawley; Heat-Shock Proteins; Cytoplasm; Molecular Chaperones
PubMed: 36260112
DOI: 10.1007/s00418-022-02158-1 -
Molecular Biology of the Cell Jan 2024α-Synuclein is a presynaptic protein that regulates synaptic vesicle (SV) trafficking. In Parkinson's disease (PD) and dementia with Lewy bodies (DLB), α-synuclein...
α-Synuclein is a presynaptic protein that regulates synaptic vesicle (SV) trafficking. In Parkinson's disease (PD) and dementia with Lewy bodies (DLB), α-synuclein aberrantly accumulates throughout neurons, including at synapses. During neuronal activity, α-synuclein is reversibly phosphorylated at serine 129 (pS129). While pS129 comprises ∼4% of total α-synuclein under physiological conditions, it dramatically increases in PD and DLB brains. The impacts of excess pS129 on synaptic function are currently unknown. We show here that compared with wild-type (WT) α-synuclein, pS129 exhibits increased binding and oligomerization on synaptic membranes and enhanced vesicle "microclustering" in vitro. Moreover, when acutely injected into lamprey reticulospinal axons, excess pS129 α-synuclein robustly localized to synapses and disrupted SV trafficking in an activity-dependent manner, as assessed by ultrastructural analysis. Specifically, pS129 caused a declustering and dispersion of SVs away from the synaptic vicinity, leading to a significant loss of total synaptic membrane. Live imaging further revealed altered SV cycling, as well as microclusters of recently endocytosed SVs moving away from synapses. Thus, excess pS129 caused an activity-dependent inhibition of SV trafficking via altered vesicle clustering/reclustering. This work suggests that accumulation of pS129 at synapses in diseases like PD and DLB could have profound effects on SV dynamics.
Topics: Animals; alpha-Synuclein; Parkinson Disease; Phosphoserine; Synapses; Synaptic Vesicles; Lampreys
PubMed: 37991902
DOI: 10.1091/mbc.E23-07-0269 -
Nature Methods Nov 2022Mass-spectrometry-based phosphoproteomics has become indispensable for understanding cellular signaling in complex biological systems. Despite the central role of...
Mass-spectrometry-based phosphoproteomics has become indispensable for understanding cellular signaling in complex biological systems. Despite the central role of protein phosphorylation, the field still lacks inexpensive, regenerable, and diverse phosphopeptides with ground-truth phosphorylation positions. Here, we present Iterative Synthetically Phosphorylated Isomers (iSPI), a proteome-scale library of human-derived phosphoserine-containing phosphopeptides that is inexpensive, regenerable, and diverse, with precisely known positions of phosphorylation. We demonstrate possible uses of iSPI, including use as a phosphopeptide standard, a tool to evaluate and optimize phosphorylation-site localization algorithms, and a benchmark to compare performance across data analysis pipelines. We also present AScorePro, an updated version of the AScore algorithm specifically optimized for phosphorylation-site localization in higher energy fragmentation spectra, and the FLR viewer, a web tool for phosphorylation-site localization, to enable community use of the iSPI resource. iSPI and its associated data constitute a useful, multi-purpose resource for the phosphoproteomics community.
Topics: Humans; Proteome; Phosphopeptides; Phosphoserine; Proteomics; Mass Spectrometry; Phosphorylation
PubMed: 36280721
DOI: 10.1038/s41592-022-01638-5 -
ChemMedChem Apr 2020The specific targeting of protein-protein interactions by phosphoserine-containing small molecules has been scarce due to the dephosphorylation of phosphoserine and its...
The specific targeting of protein-protein interactions by phosphoserine-containing small molecules has been scarce due to the dephosphorylation of phosphoserine and its charged nature at physiological pH, which hinder its uptake into cells. To address these issues, we herein report the synthesis of phosphoserine aryloxy triester phosphoramidates as phosphoserine prodrugs that are enzymatically metabolized to release phosphoserine. This phosphoserine-masking approach was applied to a phosphoserine-containing inhibitor of 14-3-3 dimerization, and the generated prodrugs exhibited improved pharmacological activity. Collectively, this provided a proof of concept that the masking of phosphoserine with biocleavable aryloxy triester phosphoramidate masking groups is a viable intracellular delivery system for phosphoserine-containing molecules. Ultimately, this will facilitate the discovery of phosphoserine-containing small-molecule therapeutics.
Topics: Amides; Dose-Response Relationship, Drug; Humans; Molecular Structure; Phosphoric Acids; Phosphorylation; Phosphoserine; Prodrugs
PubMed: 32162793
DOI: 10.1002/cmdc.202000034 -
European Journal of Pharmacology Oct 1997Phosphoserine phosphatase (EC 3.1.1.3) catalyzes the final step in the major pathway of L-serine biosynthesis in brain. This enzyme may also regulate the levels of...
Phosphoserine phosphatase (EC 3.1.1.3) catalyzes the final step in the major pathway of L-serine biosynthesis in brain. This enzyme may also regulate the levels of glycine and D-serine, the known and putative co-agonists for the glycine site of the N-methyl-D-aspartate receptor in caudal and rostral brain regions, respectively. Using L-phosphoserine as substrate, the rank order potency for inhibition of phosphoserine phosphatase was p-chloromercuriphenylsulfonic acid (CMPSA) > glycerophosphorylcholine >> hexadecylphosphocholine > or = phosphorylcholine > N-ethylmaleimide > or = L-serine > fluoride > D-2-amino-3-phosphonopropionic acid (D-AP3). Glycerylphosphorylcholine (IC50 18 microM) was found to be an uncompetitive inhibitor of phosphoserine phosphatase. Glycerylphosphorylcholine probably binds a novel site on the enzyme since the known allosteric inhibitor L-serine is highly selective for its feedback regulatory site, indicated by the inactivity of 25 L-serine analogs. Fluoride ion (IC50 770 microM) may bind the active site as has been shown for other Mg2+-dependent enzymes. The sulfhydryl reagent CMPSA is a potent, noncompetitive inhibitor of the enzyme using L-phosphoserine as substrate (IC50 9 microM) but is > 300-fold less potent using D-phosphoserine as substrate. Substrate-dependent differences are also observed with the sulfhydryl alkylator N-ethylmaleimide, which inhibits L-phosphoserine, but stimulates D-phosphoserine hydrolysis. These sulfhydryl reagents may dissociate multimeric forms of the enzyme to form monomers; the multimeric forms and monomers may preferentially cleave L- and D-phosphoserine, respectively. Phosphorylcholine esters and sulfhydryl reagents may prove useful in determining the contribution of phosphoserine phosphatase to the biosynthesis of glycine and D-serine in neuronal tissue in vitro.
Topics: Animals; Brain; Enzyme Inhibitors; Glycerylphosphorylcholine; In Vitro Techniques; Phosphoric Monoester Hydrolases; Phosphoserine; Rats; Stereoisomerism; Substrate Specificity; Sulfhydryl Reagents
PubMed: 9430431
DOI: 10.1016/s0014-2999(97)01304-6 -
Molecular and Chemical Neuropathology Aug 1991L-Phosphoserine is a membrane metabolite that is elevated in Alzheimer's disease brain. This compound has close structural similarity to L-glutamate.... (Review)
Review
L-Phosphoserine is a membrane metabolite that is elevated in Alzheimer's disease brain. This compound has close structural similarity to L-glutamate. Electrophysiological studies indicate that L-phosphoserine has an acute inhibitory effect, but a delayed excitatory action. A hypothesis is developed based on pharmacological and electrophysiological studies that suggest that the inhibition may be mediated through presynaptic inhibition of L-glutamate release or perhaps antagonism of postsynaptic kainic acid receptors. The mechanism of the delayed excitation may lie in the tendency of L-phosphoserine to mimic the action of L-2-amino-4-phosphonobutyric acid, a blocker of chloride- and calcium-sensitive L-glutamate transport. L-Phosphoserine has also been found to be a competitive antagonist at the N-methyl-D-aspartate recognition site and an antagonist of metabotropic receptor-mediated hydrolysis of inositol phospholipids. Because of these actions, there are several potentially important implications for the elevation of L-phosphoserine in Alzheimer's disease, including production memory impairment through presynaptic inhibition of L-glutamate release or blockade of postsynaptic N-methyl-D-aspartate receptors and/or blockade of certain L-glutamate transport sites resulting in increased L-glutamate levels in the synaptic cleft.
Topics: Alzheimer Disease; Aminobutyrates; Animals; Humans; Phosphoserine; Receptors, N-Methyl-D-Aspartate
PubMed: 1837714
DOI: 10.1007/BF03161056