摘要:

AbstractThe extracellular domain (621 N-terminal amino acids) of the p170 epidermal growth factor (EGF) receptor has eleven consensus N-linked glycosylation sites. When expressed in Chinese hamster ovary cells this was glycosylated with a combination of high mannose and complex chains. The latter chains were shown by chromatographic separation and mass spectrometric analysis of tryptic digests to be clustered in the EGF-binding domain. Treatment with the endoglycosidase, peptide-N-glycosidase F (PNGase F), reduced the molecular weight from 110 kDa to 75 kDa. Released oligosaccharides were characterised at high sensitivity by high pH anion exchange chromatography with pulsed amperometric detection and gas-liquid chromatography/mass spectrometry. The data were consistent with the complex chains being trisialylated tetra-antennary oligosaccharides fucosylated on the reducing terminal GlcNAc. The large hydrodynamic mass of these oligosaccharides could influence ligand binding, an effect which is likely to vary with the difference in consensus glycosylation sites of proteins related to p170 i.e. p185erbB2/neu, p180erB3and p180erbB4.

ISSN:0897-7194    

DOI:10.3109/08977199609034572

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractSuccessful pregnancy depends upon placental growth and development, which follows a specific spatial and temporal sequence. Hepatocyte Growth Factor (HGF) is a potent mitogen, morphogen and motogen to both endothelial and epithelial cell types and is linked to a tyrosine kinase, proto-oncogene,c-metreceptor. In‘normal’third trimester placentae (n=5) full thickness biopsies (obtained at Caesarean section), immunolocalisation andin situ hybridisationstudies were performed for HGF andc-met, respectively. HGF immunoreactive protein was present in mesenchymal core, the vaculosyncytial membrane (syncytotrophoblast) and the vascular endothelial cells of villous trophoblast. The HGFmRNA was present particularly strongly in the perivascular stromal cells surrounding the villous vasculature and the amnion/chorionic membranes. Immunoreactivec-metprotein was strongly localised to the endothelial cells lining the villous vasculature and the vasculosyncytial membrane. A relatively weak and diffuse hybridisation signal forc-met mRNA was present throughout the villous trophoblast, most pronounced in the vasculosyncytial membrane. These results indicate that HGF may serve as a paracrine mediator to control placental development and growth.

ISSN:0897-7194    

DOI:10.3109/08977199609034573

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractA search of the nucleic acid database of expressed sequence tags (ESTs) revealed several partial cDNA sequences that could encode proteins homologous to the ligands for Eph-related kinases (LERKs). Oligonucleotides designed from the ESTs were used to probe a human brain cDNA library and obtain overlapping clones that encoded two different novel LERKS (NLERK-1 and NLERK-2). NLERK-1 and NLERK-2 are most closely related to human LERK-2/Elk-ligand and they form a subclass of LERKs that contain a transmembrane domain and a conserved cytoplasmic domain. Full-length NLERK-1 was expressed as a glycosylated membrane protein in COS cells and was not secreted into the medium. Full-length NLERK-2 was similarly expressed in COS cells but both membranebound and a truncated, proteolytically-released form were detected. Engineered forms of both NLERK-1 and NLERK-2 lacking transmembrane and cytoplasmic domains were also expressed in COS cells and each was detected in the extracellular medium.

ISSN:0897-7194    

DOI:10.3109/08977199609034574

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor