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利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 Mef2D(肌细胞增强因子2D)属于四个转录因子家族，即Mef2A、Mef2B、MEF2C和Mef2D。该转录因子家族有一个高度保守的MADS(MCM1，AGamous，Deficiens，SRF)结构域和一个独特的MEF2结构域。这两个结构域共同构成了MEF2转录因子的N端87个氨基酸，并介导了DNA的结合、二聚化以及与多种辅激活子和辅阻遏子的相互作用。该家族的C末端结构域更具分歧性，含有转录激活结构域(TAD)。Mef2D的活性受多个翻译后修饰的调节。已知Mef2D是磷酸化、乙酰化和总甲基化的。一种相对较新的修饰，O-连接N-乙酰氨基葡萄糖(O-GlcNAc)，是一种丰富的翻译后修饰，调节几种具有不同细胞功能的磷酸化蛋白的功能。O-GlcNAc修饰核蛋白和细胞质蛋白的丝氨酸和苏氨酸，修饰后的蛋白在蛋白质相互作用、转录和信号转导中具有重要功能。O-GlcNAc与磷酸化存在复杂的相互作用，在许多情况下，磷酸化与O-GlcNAc是相互作用的。我们利用O-GlcNAc抗体进行的研究表明，O-GlcNAc修饰了Mef2D。为了了解Mef2D糖基化的功能，我们需要确定修饰的位置。对该地点的鉴定将使我们能够对该地点进行变异并进行进一步分析。加州大学旧金山分校的质谱学设备将帮助我们完成这一部分的项目，以确定O-GlcNAc的位置，并帮助我们确定相同的位置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.