ID OF A SITE IN MEF2D THAT IS MODIFIED BY O-LINKED N-ACETYLGLUCOSAMINE

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 中心，不一定是研究者的机构。 Mef 2D（Myocyte enhancer binding factor 2D）属于Mef 2A、Mef 2B、Mef 2C和Mef 2D四个转录因子家族。 该转录因子家族共享高度保守的MADS（MCM 1、Agamous、Deficiens、SRF）结构域以及独特的MEF 2结构域。 这两个结构域共同构成MEF 2转录因子的N-末端87个氨基酸，并介导DNA结合、二聚化以及与多种共激活子和共阻遏子的相互作用。 该家族的C-末端结构域更趋不同，并且包含转录激活结构域（transcriptional activation domain，简写为ESTs）。 Mef 2D的活性受多种翻译后修饰的调节。 已知Mef 2D被磷酸化、乙酰化和类小泛素化。 一种相对较新鉴定的修饰，O-连接N-乙酰葡糖胺（O-GlcNAc），是一种丰富的翻译后修饰，可调节具有不同细胞功能的几种磷酸化蛋白的功能。 O-GlcNAc修饰细胞核和细胞质蛋白质的丝氨酸和苏氨酸，修饰后的蛋白质在蛋白质相互作用、转录和信号转导中具有重要的功能。 O-GlcNAc与磷酸化存在复杂的相互作用，并且在许多情况下，已发现磷酸化与O-GlcNAc相互作用。 我们用抗O-GlcNAc的抗体进行的研究表明，Mef 2D被O-GlcNAc修饰。 为了理解Mef 2D糖基化的功能，我们需要确定修饰的位点。 对该位点的鉴定将使我们能够对该位点进行突变并进行进一步的分析。 UCSF质谱设备将帮助我们完成项目的这一部分，以确定O-GlcNAc的位点，并帮助我们确定同一位点是否也被磷酸化修饰。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Mef2D (Myocyte enhancer binding factor 2D) belongs to a family of four transcription factor namely Mef2A, Mef2B, Mef2C and Mef2D. This family of transcription factor shares a highly conserved MADS (MCM1, Agamous, Deficiens, SRF) domain, as well as a unique MEF2 domain. These two domains together constitute the N-terminal 87 amino acids of the MEF2 transcription factors, and mediate DNA binding, dimerization, and interaction with multiple coactivators and corepressors. The C-terminal domain of this family is more divergent and contains the transcriptional activation domain (TAD). The activity of Mef2D is regulated by multiple post-translational modifications. Mef2D is known to be phosphorylated, acetylated and sumoylated. A relatively newly identified modification, O-linked N-acetyl glucosamine (O-GlcNAc), is an abundant post-translational modification that modulates function of several phospho-proteins with diverse cellular functions. O-GlcNAc modifies serines and threonines of nuclear and cytoplasmic proteins and the modified proteins have important function in protein-protein interaction, transcription and signal transduction. O-GlcNAc exists in a complex interplay with phosphorylation and in many cases phosphorylation has been found to be reciprocal to O-GlcNAc. Our studies, using antibody against O-GlcNAc, show that Mef2D is modified by O-GlcNAc. To understand the function of Mef2D glycosylation, we need to identify the site of modification. Identification of the site will allow us to mutate the site and perform further analysis. The UCSF Mass Spectrometry Facility will help us with this part of the project to identify the site of O-GlcNAc and also help us identify if the same site is also modified by phosphorylation.