Structural and functional characterization of the receptor protein tyrosine phosp

受体蛋白酪氨酸磷酸的结构和功能表征

• 批准号: 7738780
• 负责人: Heidi Erlandsen
• 金额: $ 10.98万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2011-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7738780
• 关键词: Actins; Adenomatous Polyposis Coli; Adolescent; Adult; Affect; Alkaline Phosphatase; Binding; Biological Assay; Bone Density; Bone Growth; Calorimetry; Cartilage; Cell membrane; Cell physiology; Cell-Cell Adhesion; Cells; Chondrocytes; Chondrogenesis; Complex; Coupled; Cytoskeleton; Data; Degenerative polyarthritis; Dentin; Development; Dimerization; Disease; Drug Design; E-Cadherin; Endopeptidases; Engineering; Extracellular Domain; Extracellular Matrix; Future; Gene Targeting; Genes; Heparin Binding; Human; In Situ; In Vitro; Inflammatory; Integral Membrane Protein; Knowledge; Lead; Ligands; Malignant Neoplasms; Mediating; Metalloproteases; Microfilaments; Molecular; Mus; Neuroectodermal Cell; Neurons; Nitric Oxide; Normal Cell; Osteoarthrosis Deformans; Osteoblasts; Osteocalcin; Osteocytes; Osteogenesis; Osteoporosis; Patients; Phosphoproteins; Phosphoric Monoester Hydrolases; Process; Protein Dephosphorylation; Protein Tyrosine Phosphatase; Proteins; Regulation; Roentgen Rays; Signal Pathway; Signal Transduction; Site-Directed Mutagenesis; Staging; Structure; Substrate Domain; Surface Plasmon Resonance; Synovial Fluid; System; Techniques; Testing; Tissues; Tyrosine; Vascular Endothelial Growth Factors; X Chromosome; X-Ray Crystallography; base; beta catenin; bone sialoprotein; chemokine; dentin matrix protein 1; dimer; extracellular; fetal; human PTPRT protein; in vivo; inhibitor/antagonist; inorganic phosphate; mineralization; mutant; numb protein; osteoblast differentiation; pleiotrophin; public health relevance; receptor; repaired; small molecule; transcription factor

DESCRIPTION (provided by applicant): Recently, the receptor proteine tyrosine phosphatase (RPTP¿?) has been identified as involved in bone formation. RPRP¿? was strongly induced between day 5 and 25 of primary osteoblast differentiation, more so than other genes known to be induced upon terminal osteoblast differentiation such as Bglap, Ibsp, Dmp1, Akp2 and PheX. RPTP¿? ?has previously been described mainly in neuronal cells, and was the first described receptor for the heparin-binding molecule pleiotrophin (PTN), a small chemokine of 15- 17 kDa, that was also independently identified as Osteoblast-stimulating factor-1 (OSF- 1). Mice engineered to over-express PTN show a marked increase in intramembraneous bone formation and multiple effects on long-term bone growth. The molecular mechanism with which PTN exerts its stimulatory effects is not known in detail. A current hypothesis is that PTN-induced dimerization of RPTP¿?? ?results in loss of intracellular RPTP¿?? phosphatase activity. In the absence of PTN signaling, RPTP¿?? ?is shown to dephosphorylate ¿-catenin, resulting in the formation of a ¿-catenin/a-catenin/E-cadherin molecular complex, which tethers actin filaments to the cell membrane. This is necessary for normal cell-cell adhesion. PTN signaling though the RPTP¿?? ?receptor leads to decay of ¿catenin/E-cadherin complex formation, due to loss of tyrosine dephosphorylation of ¿-catenin, disruption of the actin cytoskeleton and loss of cell-cell adhesion. Our aims are to perform in vitro studies of the entire system consisting of pleiotrophin, RPTP¿??? and RPTP¿?? phosphatase-domain substrates. These studies will be highly relevant for understanding the molecular interactions between the proteins in this signaling network. Also, more importantly, biophysical characterization and three dimensional structural understanding of this newly discovered signaling system will open up a new field and lead to future structure-based drug design of new PTN/RPTP¿??? small-molecule binding agents that might be able to treat osteoarthritis, osteopenia/osteoporosis, and other diseases associated with changes in bone density. PUBLIC HEALTH RELEVANCE: The receptor protein tyrosine phosphatase ¿?? ?(RPTP¿? ) is a key transmembrane protein that regulates different aspects of normal cell function. We plan to study the interactions between this protein and its known ligand pleiotrophin plus other proteins know to interact with RPTP¿?, using a variety of biophysical techniques.

描述（申请人提供）：最近，受体蛋白酪氨酸磷酸酶（RPTP？）已经被确定为与骨形成有关。RPRP？在原代成骨细胞分化的第5天至第25天之间被强烈诱导，比已知在终末成骨细胞分化时被诱导的其他基因如Bglap、Ibsp、Dmp 1、Akp 2和PheX更强烈。RPTP？?先前主要在神经元细胞中描述，并且是肝素结合分子多效生长因子（PTN）的第一个描述的受体，PTN是一种15- 17 kDa的小趋化因子，其也被独立地鉴定为成骨细胞刺激因子-1（OSF- 1）。过表达PTN的小鼠表现出膜内骨形成的显著增加和对长期骨生长的多重影响。PTN发挥其刺激作用的分子机制尚不清楚。目前的一个假设是，PTN诱导的RPTP二聚化？?导致细胞内RPTP的丧失？？磷酸酶活性在没有PTN信号的情况下，RPTP？？?被证明可以使-catenin，导致形成<$-catenin/a-catenin/E-cadherin分子复合物，将肌动蛋白丝拴在细胞膜上。这对于正常的细胞-细胞粘附是必需的。PTN信令通过RPTP？？?受体导致连环蛋白/E-钙粘蛋白复合物形成的衰减，这是由于连环蛋白的酪氨酸去磷酸化的丧失、肌动蛋白细胞骨架的破坏和细胞-细胞粘附的丧失。我们的目标是进行体外研究的整个系统组成的多效因子，RPTP？？？RPTP？磷酸酶结构域底物。这些研究对于理解该信号网络中蛋白质之间的分子相互作用具有高度相关性。此外，更重要的是，生物物理表征和三维结构的理解，这一新发现的信号系统将开辟一个新的领域，并导致未来的结构为基础的药物设计新的PTN/RPTP？可能能够治疗骨关节炎、骨质减少/骨质疏松症和其他与骨密度变化相关的疾病的小分子结合剂。 公共卫生相关：受体蛋白酪氨酸磷酸酶？？? (RPTP¿？是一种关键的跨膜蛋白，调节正常细胞功能的不同方面。我们计划研究这种蛋白质与其已知的配体多效因子以及其他已知与RPTP相互作用的蛋白质之间的相互作用，使用各种生物物理技术。