| 翻訳と辞書 |
| Epithelial polarity ： ウィキペディア英語版 |
Epithelial polarity
Cell polarity is a fundamental feature of many types of cells. Epithelial cells are one example of a polarized cell type, featuring distinct 'apical', 'lateral' and 'basal' plasma membrane domains. Epithelial cells connect to one another via their lateral membranes to form epithelial sheets that line cavities and surfaces throughout the animal body. Each plasma membrane domain has a distinct protein composition, giving them distinct properties and allowing directional transport of molecules across the epithelial sheet. How epithelial cells generate and maintain polarity remains unclear, but certain molecules have been found to play a key role.
A variety of molecules are located at the apical membrane, but only a few key molecules act as determinants that are required to maintain the identity of the apical membrane and, thus, epithelial polarity. These molecules are the proteins Cdc42, atypical protein kinase C (aPKC), Par6, Par3/Bazooka/ASIP. Crumbs, "Stardust" and protein at tight junctions (PATJ). These molecules appear to form two distinct complexes: an aPKC-Par3-Par6 "aPKC" (or "Par") complex that also interacts with Cdc42; and a Crumbs-Stardust-PATJ "Crumbs" complex. Of these two complexes, the aPKC complex is the most important for epithelial polarity, being required even when the Crumbs complex is not. Crumbs is the only transmembrane protein in this list and the Crumbs complex serves as an apical cue to keep the aPKC complex apical during complex cellular shape changes.
==Basolateral membranes==
In the context of renal tubule physiology, the term basolateral membrane refers to the cell membrane which is oriented ''away'' from the lumen of the tubule. The principal function for this membrane is to take up metabolic waste products into the epithelial cell for disposal into the lumen where it is transported out of the body as urine. A secondary role of the basolateral membrane is to allow the recycling of desirable substrates, such as glucose, that have been rescued from the lumen of the tubule to be secreted into the interstitial fluids.〔name="pmid16403838">〕
Basal and lateral membranes share common determinants, the proteins Lethal Giant Larvae (Lgl), Discs Large (Dlg) and Scribble (Scrib). These three proteins all localize to the basolateral domain and are essential for basolateral identity and for epithelial polarity.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Epithelial polarity」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|