Muscle Cell Signaling

肌肉细胞信号传导

• 批准号: 7176181
• 负责人: HARRY W JARRETT
• 金额: $ 24.18万
• 依托单位: UNIVERSITY OF TEXAS SAN ANTONIO
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-02-01 至 2011-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7176181
• 关键词: Accounting; Actins; Affect; Anoikis; Apoptosis; Atrophic; Binding; Binding Sites; Blocking Antibodies; Body Regions; Cell Death; Cell Proliferation; Cell Survival; Cell-Matrix Junction; Cells; Cessation of life; Complex; Contracts; Cytoskeleton; Defect; Dose; Duchenne muscular dystrophy; Dystroglycan; Dystrophin; Environment; Event; Extracellular Matrix; Fiber; Functional disorder; Genes; Genetic; Glycoproteins; Heterotrimeric GTP-Binding Proteins; Homeostasis; Hypertrophy; Integrin Binding; Integrins; Investigation; JUN gene; Laboratories; Laminin; Lesion; Life; Link; Localized; Location; MAPK14 gene; MAPK8 gene; Measures; Mechanics; Mechanoreceptors; Merosin; Modeling; Motion; Muscle; Muscle Cells; Muscle Fibers; Muscular Atrophy; Muscular Dystrophies; Mutation; Myoblasts; Myopathy; Nature; PTK2 gene; Pathway interactions; Phosphorylation; Physiological; Prevention; Process; Property; Protein Isoforms; Protein Kinase; Protein Tyrosine Kinase; Proteins; Proto-Oncogene Proteins c-akt; Range; Receptor Signaling; Research Personnel; Role; SRC gene; Sarcolemma; Signal Pathway; Signal Transduction; Site; Skeletal Muscle; Stretching; Sum; Suspension substance; Suspensions; Tertiary Protein Structure; Testing; cell growth; congenital muscular dystrophy; inhibitor/antagonist; prevent; receptor; research study; response; satellite cell; src-Family Kinases; syntrophin

DESCRIPTION (provided by applicant): Many muscular dystrophies are caused by defects in the dystrophin glycoprotein complex (DGC). The DGC and integrins bind extracellular matrix laminin-2 (o2BlYl) and defects in laminin-2 or a7(31 integrin cause other myopathies. Laminin-binding to either the DGC or integrins causes changes in the cell's signaling pathways, can effect cell survival and proliferation, and is germane to the myopathies and to muscle atrophy. Cell signaling arising at laminin/DGC/integrin is already known to be quite complex. We will characterize the protein tyrosine kinase which may be one of the earliest events in this signaling and localize the site of syntrophin phosphorylation. The physiological function of this signaling is not known but may be related to mechanoreception or anoikis. When muscle is contracted or stretched, fiber strength is maintain- ed, but when unstimulated it atrophies. The laminin/DGC/integrin signaling may be a normal physiological response to this mechanical motion, maintaining the muscle. Anoikis is the process by which cells not lo- cated in a normal cellular environment undergo apoptosis. We will test these two alternative hypotheses by determining the effect of laminin/cell attachment and stretching/contraction on the cell signaling originating at the DGC and integrins and determine if apoptosis or proliferative signaling is affected. Using inhibitors and blocking antibodies, we will determine whether the DGC or a7(31 integrin is involved in the affected signaling. Other signaling pathways through p38, ERK1/2, AKT, JNK, FAK, Gs, and c-src family kinases have all been linked to the binding of extracellular matrix to the sarcolemma. The activation and location of each of these will be determined as myocytes bind extracellular matrix components and as the myocytes are stretch, held in suspension, or allowed to attach to matrix. The extent of apoptosis will also be determined and the sum of these will give a clear picture of how viability is affected by these signaling events. The five globular domains of laminin's a-subunit (LG1-5) provide binding sites for integrins and the DGC. We have expressed and purified the laminin a1-LG4-5 domain and have shown that, depending on dose, it can cause cell proliferation or death. Another collaborator has provided the Q2-LG4-5 domain protein. By comparing the effects of the two proteins on cell viability and cell signaling, we will determine the receptor responsible for proliferative and death responses and the nature of the cell death observed. By truncation mutation, we will further localize the laminin-a sequences responsible.

描述（由申请人提供）：许多肌营养不良症是由肌营养不良蛋白糖蛋白复合物（DGC）缺陷引起的。DGC和整联蛋白结合细胞外基质层粘连蛋白-2（α 2 β 1），层粘连蛋白-2或α 7 β 1整联蛋白的缺陷引起其它肌病。层粘连蛋白与DGC或整联蛋白的结合引起细胞信号传导途径的变化，可以影响细胞存活和增殖，并且与肌病和肌肉萎缩密切相关。已知层粘连蛋白/DGC/整联蛋白引起的细胞信号传导非常复杂。我们将描述蛋白酪氨酸激酶，这可能是最早的事件之一，在这个信号和本地化的网站的syntrophin磷酸化。这种信号传导的生理功能尚不清楚，但可能与机械感受或失巢凋亡有关。当肌肉收缩或伸展时，纤维强度保持艾德，但当不受刺激时，纤维就会萎缩。层粘连蛋白/DGC/整联蛋白信号传导可能是对这种机械运动的正常生理反应，维持肌肉。失巢凋亡是不位于正常细胞环境中的细胞发生凋亡的过程。我们将通过确定层粘连蛋白/细胞附着和拉伸/收缩对起源于DGC和整合素的细胞信号传导的影响来测试这两种替代假设，并确定凋亡或增殖信号传导是否受到影响。使用抑制剂和阻断抗体，我们将确定DGC或α 7 β 1整联蛋白是否参与受影响的信号传导。通过p38、ERK 1/2、AKT、JNK、FAK、Gs和c-src家族激酶的其他信号传导途径都与细胞外基质与肌膜的结合有关。当肌细胞结合细胞外基质组分时，以及当肌细胞被拉伸、保持悬浮或允许附着于基质时，将确定这些中的每一个的激活和位置。还将确定细胞凋亡的程度，并且这些的总和将给出这些信号传导事件如何影响活力的清晰画面。层粘连蛋白α-亚基的五个球状结构域（LG 1 -5）为整联蛋白和DGC提供结合位点。我们已经表达并纯化了层粘连蛋白a1-LG 4 -5结构域，并且已经表明，根据剂量，它可以引起细胞增殖或死亡。另一位合作者提供了Q2-LG 4 -5结构域蛋白。通过比较这两种蛋白对细胞活力和细胞信号传导的影响，我们将确定负责增殖和死亡反应的受体以及观察到的细胞死亡的性质。通过截短突变，我们将进一步定位层粘连蛋白-a序列。