Interactions of pleiotrophin with receptor type protein tyrosine phosphatase

多效蛋白与受体型蛋白酪氨酸磷酸酶的相互作用

• 批准号: 9988093
• 负责人: Xu Wang
• 金额: $ 20万
• 依托单位: ARIZONA STATE UNIVERSITY-TEMPE CAMPUS
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-02-01 至 2022-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9988093
• 关键词: Affinity; Binding; Binding Sites; C-terminal; Cell Differentiation process; Cell Maintenance; Chondroitin Sulfate A; Chondroitin Sulfate Proteoglycan; Chondroitin Sulfates; Complex; Core Protein; Dermatan Sulfate; Engineering; GAG Gene; Glycosaminoglycans; Growth; Health; Hematopoietic stem cells; Human; Injury; Interleukin-2; Length; Malignant Neoplasms; Mission; Modeling; Neoplasm Metastasis; Pathogenicity; Physiology; Play; Polysaccharides; Protein Tyrosine Phosphatase; Proteins; Proteoglycan; Research; Role; Signal Transduction; Structure; System; Tail; Testing; United States National Institutes of Health; Unspecified or Sulfate Ion Sulfates; angiogenesis; crosslink; cytokine; density; improved; inhibitor/antagonist; monomer; neurodevelopment; novel; novel therapeutics; overexpression; pleiotrophin; public health relevance; receptor; success; sulfation; tissue regeneration; tissue repair; tumor growth

Pleiotrophin (PTN) is a vital cytokine responsible for stimulating cell differentiation, neural development, angiogenesis and hematopoietic stem cell maintenance. Although PTN is crucial to tissue regeneration after injury, errant expression of the cytokine often leads to pathogenic conditions. Specifically, PTN is overexpressed in a large number of cancers and reduction of PTN activity decreases the growth rates and metastatic potentials of those cancers. This indicates PTN signaling maybe a valuable target for treating a number of ailments. However, little is known about the structural mechanism of PTN signaling. We want to investigate structural determinants that regulate PTN’s interactions with receptor-type protein tyrosine phosphatase zeta (PTPRZ), a chondroitin sulfate (CS) proteoglycan and the receptor associated with PTN’s mitogenic and angiogenic activities. Our hypothesis is that PTN’s two independent domains can cross link PTPRZ by binding to their glycosaminoglycan chains or core proteins, resulting in PTPRZ auto-inhibition. We want to confirm our model and investigate whether GAG-induced PTN oligomer is necessary in PTN signaling. In our preliminary studies, we have determined PTN’s structure and showed PTN’s affinity for glycosaminoglycan is dependent on the sulfation density and iduronate content of the glycan. We also showed that the C-terminal tail of PTN, known to be crucial for PTPRZ signaling for unexplained reasons, is essential to maintaining stable interactions with the type of CS found in PTPRZ, and that PTN binds to a segment of the PTPRZ protein with even higher affinity than CS, thereby providing additional mechanisms for PTPRZ crosslinking. We also showed that PTN oligomerization only happens in the presence of glycosaminoglycans and the PTN oligomerization interface most likely involve both structural domains in PTN. Building on the success of our preliminary studies, we want to further investigate structural mechanisms of PTN signaling. Specifically, we propose to: 1) Determine structures of PTN-GAG complexes with a focus on oversulfated dermatan sulfate, which can potentially be a potent PTN inhibitor. 2) Determine the oligomer structure of PTN and engineer obligatory monomers of PTN to examine the role of PTN oligomers in its interactions with PTPRZ. 3) Determine the functional impact of PTN’s interactions with the protein component of PTPRZ and find other PTN-binding sites in the PTPRZ core protein. These interactions could be a crucial part of PTN-PTPRZ signaling, therefore modulation of PTN activity is not complete without considering such interactions. 4) Investigate whether PTN’s activity is associated with its ability to crosslink proteoglycans using a novel model proteoglycan system. This system will allow us to test whether crosslinking is dependent on the core protein of PTPRZ and investigate the influence of glycan sulfation density and length on crosslinking and activity of PTN.

pleiotiotrophin（PTN）是一个重要的细胞因子，负责刺激细胞分化，神经发育， 血管生成和造血干细胞维持。尽管PTN对组织再生至关重要 损伤，细胞因子的误差表达通常会导致致病状况。具体而言，PTN是 在大量癌症中过表达和PTN活性的降低会降低生长速率和 这些癌症的转移潜力。这表明PTN信号可能是治疗A的宝贵目标 疾病数量。但是，关于PTN信号传导的结构机制知之甚少。我们想 研究调节PTN与受体型蛋白酪氨酸相互作用的结构决定剂 磷酸酶Zeta（PTPRZ），硫酸软骨（CS）蛋白聚糖和与PTN相关的接收器 有丝分裂和血管生成活性。我们的假设是PTN的两个独立领域可以交叉链接 PTPRZ通过与其糖胺聚糖链或核心蛋白结合，从而导致PTPRZ自动抑制作用。我们 想要确认我们的模型并研究PTN信号传导中是否需要GAG诱导的PTN低聚物。 在我们的初步研究中，我们确定了PTN的结构，并显示了PTN的亲和力 糖胺聚糖取决于聚糖的硫酸密度和同化含量。我们也表明 PTN的C末端尾巴，已知对于PTPRZ信号至关重要，出于意外原因，对于 与PTPRZ中发现的CS类型保持稳定的相互作用，并且PTN与该段结合 PTPRZ蛋白具有比CS更高的亲和力，从而为PTPRZ提供了其他机制 交联。我们还表明，PTN寡聚仅在糖胺聚糖存在下发生 PTN低聚界面很可能涉及PTN中的两个结构域。建立在 初步研究的成功，我们希望进一步研究PTN信号传导的结构机制。 具体而言，我们建议：1）确定PTN-GAG复合物的结构，重点是 皮肤硫酸盐，可能是潜在的PTN抑制剂。 2）确定PTN的低聚物结构 PTN的工程师强制性单体检查PTN低聚物在与PTPRZ相互作用中的作用。 3）确定PTN与PTPRZ蛋白质成分相互作用的功能影响，并找到其他 PTPRZ核心蛋白中的PTN结合位点。这些相互作用可能是PTN-PTPRZ的关键部分 信号传导，因此，如果不考虑这种相互作用，对PTN活性的调节尚未完成。 4） 研究PTN的活动是否与使用新型模型交联蛋白聚糖的能力有关 蛋白聚糖系统。该系统将使我们能够测试交联是否取决于 PTPRZ并研究了聚糖硫化密度和长度对PTN的交联和活性的影响。