【项目简介】
Fibroblast growth factor receptor 4 (FGF R4), also known as CD334, is a 110 kDa glycosylated transmembrane receptor tyrosine kinase. Mature human FGF R4 consists of a 348 amino acid (aa) extracellular domain (ECD) with three Ig‑like domains, a 21 aa transmembrane segment, and a 412 aa cytoplasmic domain that contains the tyrosine kinase domain. Within the ECD, human FGF R4 shares 90% and 88% aa sequence identity with mouse and rat FGF R4, respectively. Alternate splicing generates a potentially secreted isoform with a substitution encompassing the transmembrane segment. A 65 kDa N‑terminally truncated isoform lacks the signal peptide and first two Ig‑like domains. This isoform is produced in human pituitary adenomas and is constitutively phosphorylated and oncogenic. FGF R4 is widely expressed during embryonic development and in adult liver, kidney, and lung. It binds FGF acidic, FGF basic, FGF‑8, -15, and -19. FGF R4 associates with beta-Klotho and sulfated glycosaminoglycans, and these interactions increase the affinity of FGF R4 for its ligands as well as its signaling capacity. 
 
【检验原理】
本试剂盒采用双抗体夹心ELISA法。酶标微孔板上预包被有抗人FGFR4抗体，当加入标准品和待测样本时，标准品和待测样本中的人FGFR4会和该抗体结合。洗板后，游离的其他成分被洗去，加入辣根过氧化物酶标记的的抗人FGFR4抗体可与被酶标板捕获的人FGFR4结合，形成“包被抗人FGFR4抗体+人FGFR4+抗人FGFR4抗体-HRP”免疫复合物。当加入TMB显色底物后，复合物上连接的HRP催化底物反应，生成蓝色产物，终止反应后变为黄色。在450nm处测定OD值，人FGFR4浓度与OD450值之间呈正比，可通过绘制标准曲线求出标本中人FGFR4的浓度。