生物谷報(bào)道：美國科學(xué)家在6月號的《自然—化學(xué)生物學(xué)》（Nature Chemical Biology）上發(fā)表最新文章說,，腦部刺激會(huì)導(dǎo)致神經(jīng)細(xì)胞內(nèi)蛋白質(zhì)糖分含量的變化，這意味著糖修飾可能是大腦信號傳輸?shù)囊粋€(gè)重要使者,。
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眾所周知,，在細(xì)胞信號的傳輸中,，絲氨酸和蘇氨酸殘基的磷酸化水平的變化發(fā)揮了作用。糖基化是糖基吸附在蛋白質(zhì)上而導(dǎo)致其性能改變的一種作用。雖然絕大部分糖基化發(fā)生在細(xì)胞外的蛋白質(zhì)上,，但一種名為O位N-乙酰葡萄糖胺(O-GlcNAc)的糖基修飾卻吸附在細(xì)胞外蛋白質(zhì)的絲氨酸和蘇氨酸殘基上,。
因?yàn)榱姿峄蚈-GlcNAc修飾均嚴(yán)格發(fā)生在同一氨基酸的側(cè)鏈上，所以,，O-GlcNAc對細(xì)胞的信號傳輸來說應(yīng)該十分重要,。但是，科學(xué)家們一直缺少在活體內(nèi)精確鑒別O-GlcNAc修飾的工具,，因而很難對這一假說進(jìn)行驗(yàn)證,。
Linda Hsieh-Wilson和同事發(fā)明了一種蛋白質(zhì)組學(xué)方法，利用質(zhì)譜分析法確定活體中O-GlcNAc的水平,。當(dāng)他們將一種興奮劑注入小鼠體時(shí),，他們在小鼠大腦中的特定位置發(fā)現(xiàn)了糖水平的變化。利用這些信息,，科學(xué)家們就有可能研究O-GlcNAc在大腦功能中的確切作用了,。
原始出處:
Nature Chemical Biology 3, 339-348 (2007)
doi:10.1038/nchembio881
Probing the dynamics of O-GlcNAc glycosylation in the brain using quantitative proteomics
Nelly Khidekel1, Scott B Ficarro2, Peter M Clark1, Marian C Bryan1, Danielle L Swaney3, Jessica E Rexach4, Yi E Sun4, Joshua J Coon3, Eric C Peters2 & Linda C Hsieh-Wilson1
Abstract
The addition of the monosaccharide -N-acetyl-D-glucosamine to proteins (O-GlcNAc glycosylation) is an intracellular, post-translational modification that shares features with phosphorylation. Understanding the cellular mechanisms and signaling pathways that regulate O-GlcNAc glycosylation has been challenging because of the difficulty of detecting and quantifying the modification. Here, we describe a new strategy for monitoring the dynamics of O-GlcNAc glycosylation using quantitative mass spectrometry-based proteomics. Our method, which we have termed quantitative isotopic and chemoenzymatic tagging (QUIC-Tag), combines selective, chemoenzymatic tagging of O-GlcNAc proteins with an efficient isotopic labeling strategy. Using the method, we detect changes in O-GlcNAc glycosylation on several proteins involved in the regulation of transcription and mRNA translocation. We also provide the first evidence that O-GlcNAc glycosylation is dynamically modulated by excitatory stimulation of the brain in vivo. Finally, we use electron-transfer dissociation mass spectrometry to identify exact sites of O-GlcNAc modification. Together, our studies suggest that O-GlcNAc glycosylation occurs reversibly in neurons and, akin to phosphorylation, may have important roles in mediating the communication between neurons.
Division of Chemistry and Chemical Engineering and Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California 91125, USA.
Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, USA.
Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Mental Retardation Research Center, Department of Psychiatry and Biobehavioral Sciences and Department of Molecular and Medical Pharmacology, and Neuropsychiatric Institute, The David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA.
Correspondence to: Linda C Hsieh-Wilson1 Email: [email protected]
