GLYCAN MEDIATED REGULATION OF CD44 FUNCTION

描述（申请人的描述）：大多数人类癌症死亡 是由于转移，这是一个在分子水平上知之甚少的过程， 和细胞水平。 在转移的多步骤过程中， 细胞粘附分子的重要作用。 CD44，细胞表面 透明质酸（HA）受体，在细胞粘附中起作用，细胞 迁移和细胞活化，已经被牵连在这个过程中， 转移 CD44具有调节其配体亲和力的特性。 糖基化在调节CD 44介导的透明质酸结合中的作用 因此将进行审查。 这项研究与候选人的观点一致。 长期目标是阐明足够详细的机制， 糖基化调节细胞粘附分子功能， 作为转移的干预。 初步研究 已经确定了寡糖结构， CD44的HA结合特性。 本提案旨在确定 结构受到生物学调节，并阐明酶的基础 用于调节功能上重要的聚糖结构。 后 关键糖基转移酶的鉴定， 细胞调节CD44糖基化作为整合细胞行为的一部分 将被定义。 研究的机制包括合成的 糖基转移酶表达，糖基转移酶磷酸化，CD44 可变RNA剪接和相互作用的糖基转移酶。 CD44 寡糖结构将通过糖苷酶消化而改变， 糖基转移酶调节 免疫原性CD44 HA亲和力将是 通过亲和毛细管电泳测定。 结构/功能 将得出相关性。 CD44糖基化的生理变化和 透明质酸亲和性将在细胞活化时进行测试。 的效果 通过糖基转移酶操纵CD44 HA-亲和力的转移 将使用体内模型确定调节。 这项建议会 作为基础，制定一个通用的方法来定义监管 糖基化在细胞-细胞和细胞-基质粘附中的作用。

DESCRIPTION (Applicant's Description): The majority of human cancer deaths are due to metastasis, a process that is poorly understood at the molecular and cellular levels. In the multistep process of metastasis one expects significant roles for cell adhesion molecules. CD44, a cell surface receptor for hyaluronan (HA) that functions in cell adhesion, cell migration, and cell activation, has been implicated in the process of metastasis. CD44 has the property of regulated affinity for its ligand. The role of glycosylation in regulating CD44-mediated hyaluronan binding will therefore be examined. This study is consistent with the candidate's long-term objective of elucidating enough detail of the mechanism by which glycosylation regulates cell adhesion molecule function to enable modulation of this mechanism as an intervention f o r metastasis. Preliminary studies have identified oligosaccharide structures which impact the intrinsic HA-binding properties of CD44. The present proposal aims to determine which structures are biologically regulated and to elucidate the enzymatic basis for regulation of the functionally i m portant glycan structure. After identification of the key glycosyltransferase, the mechanism employed by the cell to regulate CD44 glycosylation as part of an integrated cell behavior will be defined. Mechanisms to be examined include synthetic glycosyltransferase expression, glycosyltransferase phosphorylation, CD44 alternative RNA splicing, and interacting glycosyltransferases. CD44 oligosaccharide structure will be c h a n ged by glycosidase digestion and glycosyltransferase modulation. I n t rinsic CD44 HA-affinity will be determined by affinity capillary e l e ctrophoresis. Structure/function correlations will be drawn. A physiologic change in CD44 glycosylation and hyaluronan-affinity will be tested upon cellular activation. The effects on metastasis of manipulating CD44 HA-affinity by glycosyltransferase modulation will be determined using an in vivo model. This proposal will serve as a basis to develop a general approach to defining the regulatory role of glycosylation in cell-cell and cell-matrix adhesion.