6att | pdb_00006att
39S Fab bound to HER2 ecd
Structural highlights
Disease[ERBB2_HUMAN] Defects in ERBB2 are a cause of hereditary diffuse gastric cancer (HDGC) [MIM:137215]. A cancer predisposition syndrome with increased susceptibility to diffuse gastric cancer. Diffuse gastric cancer is a malignant disease characterized by poorly differentiated infiltrating lesions resulting in thickening of the stomach. Malignant tumors start in the stomach, can spread to the esophagus or the small intestine, and can extend through the stomach wall to nearby lymph nodes and organs. It also can metastasize to other parts of the body. Defects in ERBB2 are involved in the development of glioma (GLM) [MIM:137800]. Gliomas are central nervous system neoplasms derived from glial cells and comprise astrocytomas, glioblastoma multiforme, oligodendrogliomas, and ependymomas. Defects in ERBB2 are a cause of susceptibility to ovarian cancer (OC) [MIM:167000]. Ovarian cancer common malignancy originating from ovarian tissue. Although many histologic types of ovarian neoplasms have been described, epithelial ovarian carcinoma is the most common form. Ovarian cancers are often asymptomatic and the recognized signs and symptoms, even of late-stage disease, are vague. Consequently, most patients are diagnosed with advanced disease. Defects in ERBB2 may be a cause of lung cancer (LNCR) [MIM:211980]. LNCR is a common malignancy affecting tissues of the lung. The most common form of lung cancer is non-small cell lung cancer (NSCLC) that can be divided into 3 major histologic subtypes: squamous cell carcinoma, adenocarcinoma, and large cell lung cancer. NSCLC is often diagnosed at an advanced stage and has a poor prognosis. Defects in ERBB2 are a cause of gastric cancer (GASC) [MIM:613659]. A malignant disease which starts in the stomach, can spread to the esophagus or the small intestine, and can extend through the stomach wall to nearby lymph nodes and organs. It also can metastasize to other parts of the body. The term gastric cancer or gastric carcinoma refers to adenocarcinoma of the stomach that accounts for most of all gastric malignant tumors. Two main histologic types are recognized, diffuse type and intestinal type carcinomas. Diffuse tumors are poorly differentiated infiltrating lesions resulting in thickening of the stomach. In contrast, intestinal tumors are usually exophytic, often ulcerating, and associated with intestinal metaplasia of the stomach, most often observed in sporadic disease. Note=Chromosomal aberrations involving ERBB2 may be a cause gastric cancer. Deletions within 17q12 region producing fusion transcripts with CDK12, leading to CDK12-ERBB2 fusion leading to truncated CDK12 protein not in-frame with ERBB2. Function[ERBB2_HUMAN] Protein tyrosine kinase that is part of several cell surface receptor complexes, but that apparently needs a coreceptor for ligand binding. Essential component of a neuregulin-receptor complex, although neuregulins do not interact with it alone. GP30 is a potential ligand for this receptor. Regulates outgrowth and stabilization of peripheral microtubules (MTs). Upon ERBB2 activation, the MEMO1-RHOA-DIAPH1 signaling pathway elicits the phosphorylation and thus the inhibition of GSK3B at cell membrane. This prevents the phosphorylation of APC and CLASP2, allowing its association with the cell membrane. In turn, membrane-bound APC allows the localization of MACF1 to the cell membrane, which is required for microtubule capture and stabilization.[1] [2] [3] [4] [5] [6] In the nucleus is involved in transcriptional regulation. Associates with the 5'-TCAAATTC-3' sequence in the PTGS2/COX-2 promoter and activates its transcription. Implicated in transcriptional activation of CDKN1A; the function involves STAT3 and SRC. Involved in the transcription of rRNA genes by RNA Pol I and enhances protein synthesis and cell growth.[7] [8] [9] [10] [11] [12] Publication Abstract from PubMedPathways of human EGF receptors are activated upon ligand dependent or independent homo or heterodimerization and their subsequent transphosphorylation. Overexpression of these receptors positively correlates with transphosphorylation rates and increased tumor growth rates. MEDI4276, an anti human epidermal growth factor receptor 2 (HER2) biparatopic antibody drug conjugate, has two paratopes within each of antibody arms. One, 39S, is aiming at the HER2 site involved in receptor dimerization and the second, single chain fragment (scFv) mimicking trastuzumab. Here we present the cocrystal structure of the 39S Fab/HER2 and along with biophysical and functional assays determine the corresponding epitope of MEDI4276 and its underlying mechanism of action. Our results reveal that MEDI4276s uniqueness is based, first, upon its 39S paratopes ability to block HER2 homo or heterodimerization and, second, on its ability to cluster the receptors on the surface of receptor overexpressing cells. Structural insights into the mechanism of action of a biparatopic anti-HER2 antibody.,Oganesyan V, Peng L, Bee JS, Li J, Perry SR, Comer F, Xu L, Cook K, Senthil K, Clarke L, Rosenthal K, Gao C, Damschroder M, Wu H, Dall'Acqua WF J Biol Chem. 2018 Apr 18. pii: M117.818013. doi: 10.1074/jbc.M117.818013. PMID:29669810[13] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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