ErbB signaling is implicated in the pathology of various types of carcinoma. Ligand binding to the extracellular domain of ErbB induces conformational changes that lead to homo- or heterodimerization of the receptors and subsequent signaling. It has been reported that N-glycans of the ErbB family regulate its function. We previously reported that N-glycans of EGFR are involved in receptor dimerization and endocytosis. N-glycans of ErbB3 are also involved in receptor dimerization and activation status; deletion of the N-glycan on Asn418 of ErbB3 leads to both spontaneous homodimerization of ErbB3 and heterodimerization of ErbB2-ErbB3. The promoted heterodimerization with ErbB2 leads to upregulation of receptor tyrosine phosphorylation, downstream signalings, and transforming activity. We recently found that N-glycans of ErbB4 also regulate ligand-induced signaling. Thus, N-glycans of the ErbB family seem to play an important role in receptor activation, especially in receptor dimerization. To examine the role of N-glycans of the ErbB in detail, we prepared a wild type and an N-glycan deleted mutant of sErbB3 (domains I, II, III and IV) and compared their properties. When added to culture cells expressing ErbB2 and ErbB3, the sErbB3 N418Q mutant downregulated the heregulin b signaling more effectively than the wild type sErbB3. Through mass spectrometry analysis, we were able to determine the structure of the N-glycan on Asn418 of sErbB3. This suggests that the specific N-glycan of sErbB3 regulates the binding status of sErbB3 to ligands or receptors. We consider that the sErbB3 N418Q mutant is a potent inhibitor of transforming activity of ErbB, and may have therapeutic applications in cancer.
저자
Motoko Takahashi [ Department of Biochemistry, Sapporo Medical University School of Medicine ]
Yoshinao Wada [ Research Institute, Osaka Medical Center for Maternal and Child Health ]
Michiko Tajiri [ Research Institute, Osaka Medical Center for Maternal and Child Health ]
Motoko Araki [ Department of Biochemistry, Sapporo Medical University School of Medicine ]
Yoshiki Yamaguchi [ Disease Glycomics Team, Systems Glycobiology Research Group, RIKEN ]
Naoyuki Taniguchi [ Disease Glycomics Team, Systems Glycobiology Research Group, RIKEN; The Institute of Scientific and Industrial Research, Osaka University ]
YoshioKuroki [ Department of Biochemistry, Sapporo Medical University School of Medicine ]
본 학회는 화학, 생화학, 분자생물학, 미생물학, 식품공학, 의학, 약학, 유전공학 및 생물공학, 환경 및 기타 공업 등 전 분야의 탄수화물관련 이론과 기술을 연구 발전시키고 산학협동을 통해 이를 보급하여 국내 관련 산업의 발전 및 국민생활의 과학화에 기여하고자 하며, 이러한 목표와 비젼의 실현을 위해 회원들이 적극적인 참여와 활동을 전개하고자 한다.