Structural basis of O-GlcNAc recognition by mammalian 14-3-3 proteins

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

<p id="d4269100e279">O-GlcNAc is an abundant, reversible posttranslational modification (PTM) of nuclear and cytoplasmic proteins in animals and plants. O-GlcNAc regulates a wide range of biological processes, and aberrant O-GlcNAcylation is implicated in numerous human diseases. However, key aspects of O-GlcNAc signaling remain poorly understood. For example, it is not known whether “reader” proteins exist to recognize and bind to O-GlcNAc, as is true for many other PTMs. We used a biochemical method to identify candidate human O-GlcNAc reader proteins, and then characterized them at the biochemical and biophysical levels. Our results address a significant gap in the cell signaling field by revealing the biochemical and structural basis for the recognition of O-GlcNAc by conserved human proteins. </p><p class="first" id="d4269100e282">O-GlcNAc is an intracellular posttranslational modification that governs myriad cell biological processes and is dysregulated in human diseases. Despite this broad pathophysiological significance, the biochemical effects of most O-GlcNAcylation events remain uncharacterized. One prevalent hypothesis is that O-GlcNAc moieties may be recognized by “reader” proteins to effect downstream signaling. However, no general O-GlcNAc readers have been identified, leaving a considerable gap in the field. To elucidate O-GlcNAc signaling mechanisms, we devised a biochemical screen for candidate O-GlcNAc reader proteins. We identified several human proteins, including 14-3-3 isoforms, that bind O-GlcNAc directly and selectively. We demonstrate that 14-3-3 proteins bind O-GlcNAc moieties in human cells, and we present the structures of 14-3-3β/α and γ bound to glycopeptides, providing biophysical insights into O-GlcNAc-mediated protein–protein interactions. Because 14-3-3 proteins also bind to phospho-serine and phospho-threonine, they may integrate information from O-GlcNAc and O-phosphate signaling pathways to regulate numerous physiological functions. </p>

Related collections

Most cited references 62

Record: found
Abstract: found
Article: found

Is Open Access

PhosphoSitePlus: a comprehensive resource for investigating the structure and function of experimentally determined post-translational modifications in man and mouse

Peter V. Hornbeck, Jon M. Kornhauser, Sasha Tkachev … (2011)

PhosphoSitePlus (http://www.phosphosite.org) is an open, comprehensive, manually curated and interactive resource for studying experimentally observed post-translational modifications, primarily of human and mouse proteins. It encompasses 1 30 000 non-redundant modification sites, primarily phosphorylation, ubiquitinylation and acetylation. The interface is designed for clarity and ease of navigation. From the home page, users can launch simple or complex searches and browse high-throughput data sets by disease, tissue or cell line. Searches can be restricted by specific treatments, protein types, domains, cellular components, disease, cell types, cell lines, tissue and sequences or motifs. A few clicks of the mouse will take users to substrate pages or protein pages with sites, sequences, domain diagrams and molecular visualization of side-chains known to be modified; to site pages with information about how the modified site relates to the functions of specific proteins and cellular processes and to curated information pages summarizing the details from one record. PyMOL and Chimera scripts that colorize reactive groups on residues that are modified can be downloaded. Features designed to facilitate proteomic analyses include downloads of modification sites, kinase–substrate data sets, sequence logo generators, a Cytoscape plugin and BioPAX download to enable pathway visualization of the kinase–substrate interactions in PhosphoSitePlus®.

0 comments Cited 573 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Cross talk between O-GlcNAcylation and phosphorylation: roles in signaling, transcription, and chronic disease.

Gerald Hart, Chad Slawson, Genaro Ramirez-Correa … (2011)

O-GlcNAcylation is the addition of β-D-N-acetylglucosamine to serine or threonine residues of nuclear and cytoplasmic proteins. O-linked N-acetylglucosamine (O-GlcNAc) was not discovered until the early 1980s and still remains difficult to detect and quantify. Nonetheless, O-GlcNAc is highly abundant and cycles on proteins with a timescale similar to protein phosphorylation. O-GlcNAc occurs in organisms ranging from some bacteria to protozoans and metazoans, including plants and nematodes up the evolutionary tree to man. O-GlcNAcylation is mostly on nuclear proteins, but it occurs in all intracellular compartments, including mitochondria. Recent glycomic analyses have shown that O-GlcNAcylation has surprisingly extensive cross talk with phosphorylation, where it serves as a nutrient/stress sensor to modulate signaling, transcription, and cytoskeletal functions. Abnormal amounts of O-GlcNAcylation underlie the etiology of insulin resistance and glucose toxicity in diabetes, and this type of modification plays a direct role in neurodegenerative disease. Many oncogenic proteins and tumor suppressor proteins are also regulated by O-GlcNAcylation. Current data justify extensive efforts toward a better understanding of this invisible, yet abundant, modification. As tools for the study of O-GlcNAc become more facile and available, exponential growth in this area of research will eventually take place.

0 comments Cited 428 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

The structural basis for 14-3-3:phosphopeptide binding specificity.

Michael Yaffe, Katrin Rittinger, Stefano Volinia … (1997)

The 14-3-3 family of proteins mediates signal transduction by binding to phosphoserine-containing proteins. Using phosphoserine-oriented peptide libraries to probe all mammalian and yeast 14-3-3s, we identified two different binding motifs, RSXpSXP and RXY/FXpSXP, present in nearly all known 14-3-3 binding proteins. The crystal structure of 14-3-3zeta complexed with the phosphoserine motif in polyoma middle-T was determined to 2.6 A resolution. The bound peptide is in an extended conformation, with a tight turn created by the pS +2 Pro in a cis conformation. Sites of peptide-protein interaction in the complex rationalize the peptide library results. Finally, we show that the 14-3-3 dimer binds tightly to single molecules containing tandem repeats of phosphoserine motifs, implicating bidentate association as a signaling mechanism with molecules such as Raf, BAD, and Cbl.