CD43 REGULATION OF IMMUNE RESPONSES

CD 43是T细胞表面上最丰富的蛋白质之一。然而，关于这种分子的功能，文献中充满了看似矛盾的发现。特别地，已经提出CD 43作为共刺激分子和负调节分子两者起作用。这些相互矛盾的假设是基于这样的观察，即交联CD 43和CD 43缺陷具有相同的净效应。在这两种情况下，T细胞对刺激的反应增强。其次，我们发现当T细胞与APC相互作用时，CD 43自然地被排除在接触位点之外。总之，这些数据支持这样的假设，即由于其丰度和高度糖基化的性质，CD 43充当T细胞相互作用的屏障。我们已经发现，CD 43与至少7种磷酸化蛋白相关，其中一种是TCR信号转导的关键参与者。我们相信，了解1）CD 43调节的机制，2）由于与CD 43调节的细胞质尾相关而移出相互作用位点的蛋白质，2）由于与CD 43调节的细胞质尾相关而移出相互作用位点的蛋白质CD 43的细胞质尾，以及3）CD 43调节的功能后果，将导致阐明这种蛋白质在免疫调节中的作用。因此，中心假设 该提议的一个要点是，CD 43远离T细胞的独特能力：APC相互作用位点是CD 43调节T细胞功能的机制。因此，本基金的目标是确定T细胞免疫反应的分子相互作用。为了实现这些目标，我们提出了以下具体目标：（1）确定CD 43运动是否通过细胞质与细胞骨架的相互作用发生。我们假设一个由内/外信号转导入的CD 43-/- T细胞，以确定高电荷的CD 43胞外区和胞内区在调节CD 43自T细胞-APC相互作用位点中的作用。(2)从T细胞-APC相互作用位点阐明参与CD 43调节的信号转导途径。我们假设T细胞受体信号通过细胞内蛋白质中间体的结合导致CD 43的磷酸化和调节。为了验证这一假设，CD 43通过调节远离T细胞：APC相互作用位点来影响T细胞应答，并且在这种情况下，CD 43调节缀合物形成并特异性地从活化位点去除TCR信号转导分子。为了检验这一假设，将通过比较野生型、CD 43-/-和已经用具有改变的调节能力的突变体CD 43分子重建的CD 43-/-细胞的功能能力来检验CD 43调节对T细胞功能的影响。

CD43 is unarguably one of the most abundant proteins on the T cell surface. However, the literature is full of seemingly contradictory findings on the function of this molecule. In particular, CD43 has been proposed to function as both a co-stimulatory molecule and a negative regulating molecule. These contradictory hypotheses are based on the observation that cross-linking CD43 and CD43-deficiency have the same net effect. in both situations the T cells have augmented responses to stimulus. Second, we find that when T cells interact with APC, CD43 is naturally excluded from the contact site. Together, these data support the hypothesis that, due its abundance and highly glycosylated nature, CD43 acts as a barrier to T cell interactions. We have found that CD43 associates at least 7 phosphorylated proteins, one of which is a key player in the TCR signal transduction. We believe that understanding 1) the mechanism of CD43 modulation, 2) the proteins that move out of the interaction site due to their association with the cytoplasmic tail of CD43 modulation, 2) the proteins that move out of the interaction site due to their association with the cytoplasmic tail of CD43, and 3) the functional consequences of CD43 modulation, will lead to the elucidation of the role this protein plays in immune regulation. Thus, the central hypothesis of this proposal is that the unique ability of CD43 to move away from the T cell: APC interaction site is the mechanism by which CD43 regulates T cell function. Therefore, the goal of this grant is to identify the molecular interactions T cell immune responses. To achieve these goals, we propose the following specific aims: (1) Determine whether CD43 movement occurs through cytoplasmic interactions with the cytoskeleton. We hypothesize that an inside/out signal from the transfected into a CD43-/- T cells to determine the role of highly charged extra-cellular region of CD43 and the intracellular region in the modulation of CD43 from the T cell-APC interaction site. (2) To elucidate the signal transduction pathways involved in CD43 modulation from the T cell-APC interaction site. We hypothesize that T cell receptor signaling leads to the phosphorylation and modulation of CD43 via the association of intracellular protein intermediates. To test this hypothesize that CD43 influences T cell responses by modulating away from the T cell: APC interaction site and that in dong so, CD43 regulates conjugate formation and specifically removes TCR signal transduction molecules from the site of activation. To test this hypothesis, the effect of CD43 modulation on T cell function will be tested by comparing the functional capacity of wild type, CD43-/-, and CD43-/- cells that have been reconstituted with mutant CD43 molecules that have altered modulating abilities.