| 特集名 | 消化管機能と受容体 -- 臨床とのかかわり | |
|---|---|---|
| 題名 | EGF受容体 | |
| 発刊年月 | 2000年 04月 | |
| 著者 | 城 卓志 | 名古屋市立大学医学部第一内科 |
| 【 要旨 】 | EGF受容体は分子内に有するキナーゼ領域の相同性から,現在4種類の受容体が存在することが知られている(erbB1～4).一方,リガンドであるEGFにも,前駆体を含めて構造の類似する分子が,EGF以外にtransforming growth factor-α,heparin binding EGF like growth factor,tomoregulin,amphiregulin,betacellulin,heregulinなど複数存在することが知られている.heregulinは,erbB3,4のリガンドとして知られ,他はおもにEGF受容体(erbB1)に結合すると考えられ,erbB2のリガンドは未だ知られていない.しかし,種類の違う受容体が2量体を形成し,直接の結合がなくとも活性化を受けるメカニズムも知られている.今後,EGF受容体の生理・病態的意義はこうした複数のリガンドと受容体に拡大してとらえていく必要がある. | |
| Theme | The Role of Receptors in Gastrointestinal Functions | |
|---|---|---|
| Title | EGF Receptor | |
| Author | Takashi Joh | First Department of Internal Medicine, Nagoya City University Medical School |
| [ Summary ] | Members of the epidermal growth factor(EGF) family of tyrosine kinase receptors(erbB1-4) are involved in the regulation of cell growth and differentiation, and are found to be expressed in gastrointestinal tract and cancers. The receptors are located at the cell surface, where the binding of a ligand activates a tyrosine kinase in the intracellular region of the receptor to phosphorylates on a number of intracellular substrates which activate intracellular pathways. Multiple ligands such as EGF, transforming growth factor (TGF)-a, heparin binding EGF like growth factor(HB-EGF), tomoregulin(TR), amphiregulin, and betacellulin are known to bind directly to EGFR, none(at present) to erbB-2. A family of ligands called heregulins or neuregulins bind to both erbB-3 and erbB-4. It is now apparent that the receptors are functioning in various heterodimeric pairs, which are formed depending on their concentratinos. Both tyrosine kinase regions of heterodimeric pairs can be activated by binding particular ligands in the environment to one of heterodimeric receptors. | |