| 翻訳と辞書 |
TBC domain
The TBC (Tre-2/Bub2/Cdc16) is identified as a domain of some proteins or as a protein motif and widely recognized as a conserved one that englobes approximately 200 amino acids in all eukaryotes. However, it was at first identified as a conserved domain among the tre-2 oncogene product and the yeast cell cycle regulators. It has been shown that humans have almost 42 different TBC proteins which differ from each other by having additional motifs and domains (GRAM, RUN, PTB…) and add functional diversification to the family .
The most well known of this protein group are TBC1D1 and TBC1D4 which are directly associated with functional diseases. Moreover, most of them have really close relations with other protein domains. For example, it’s been demonstrated that some of them act like a GAP (GTPase-activating protein) for small GTPases: Rab activity is modulated in part by GTPase-activating proteins (GAPs) and many of these RabGAPs share a Tre2/Bub2/Cdc16(TBC)-domain architecture. However, it is needed much research on these kind of proteins and in this article it explains what is known by now.
File:Esquema rab.jpg
Picture 1. A Rab Cycle in membrane trafficking: ''The cycle between the GTP-bound inactive state and the GTP- bound active state is leaded by the Rab protein and regulated by an activating enzyme GEF and an inactivating enzyme GAP which in this case could be the TBC protein. Hereafter, the activated form of Rab, GTP-bound, is incorporated to a specific organelle or vesicle and promotes its transport by interacting with a specific effector molecule. GTPase-activating proteins (GAPs) limit the duration of the active state and accelerate the slow intrinsic rate of GTP hydrolysis.''
==Functions==
TBC mainly functions as a specific Rab GAP (GTPases activating proteins) by being used as tools to inactivate specific membrane trafficking events. GAPs serve to increase GTPase activity by contributing the residues to the active site and promoting conversion from GTP to GDP form. Such activity of TBC proteins does not always require a close physical interaction although few TBC proteins have shown clear GAP activity towards their binding Rabs. Rab families contribute to defining organelles and controlling specificity and rate of transport through individual pathways. Therefore, TBC Rab-GAPS are essential regulators of intracellular and membrane transports as well as central participants in signal transduction. Nevertheless not all TBC may have a primary role as a Rab-GAP and conversely, not all Rab-GAP contain TBC. In addition, the fact that this family has been poorly studied makes it then further complicated.
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「TBC domain」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.
|
|