tailieunhanh - Cellular functions of the 26s proteasome

The 26S proteasome plays a critical role in many cellular processes by degrading a wide range of both short-lived and long-lived proteins. In this review, proteasome structure and the mechanisms of substrates targeting to the 26S proteasome are described. | Turk J Biol 28 (2004) 31-38 © TÜB‹TAK Cellular Functions of the 26S Proteasome Azmi YERL‹KAYA Department of Biology, Faculty of Art & Science, Dumlup›nar University, 43100, Kütahya - TURKEY Received: Abstract: The 26S proteasome plays a critical role in many cellular processes by degrading a wide range of both short-lived and long-lived proteins. In this review, proteasome structure and the mechanisms of substrates targeting to the 26S proteasome are described. In addition, this review focuses on the cellular functions that are affected after inhibition of the proteasome, including immune-response, cell-cycle, and transcription. The proteasome is involved in these cellular processes because it degrades numerous short-lived proteins and regulatory proteins that control these cellular functions. Even though it is known that inhibition of the 26S proteasome results in the induction of the synthesis of heat-shock proteins (., Hsp 70), several groups indicated that 26S proteasome inhibition also causes a significant loss of global protein synthesis activity in a very short time. Key Words: 26S proteasome; proteasome inhibitors; transcription; translation. 26S Protezomun Hücresel Görevleri Özet: 26S protezom, bir çok uzun-ömürlü ve k›sa-ömürlü proteinleri y›karak çok say›da hücresel fonksiyonda önemli roller oynamaktad›r. Bu derlemede, protezomun yap›s› ve substratlar›n 26S protezoma gönderilme mekanizmalar› aç›klanm›flt›r. Ayr›ca, bu derleme ba¤›fl›kl›k-sistemi, hücre-döngüsü ve transkripsiyon gibi protezomun inhibisyonundan etkilenen hücresel fonksiyonlar üzerinde özenle durmufltur. Protezom, bu hücresel ifllemlere onlar›n fonksiyonlar›n› kontrol eden bir çok k›sa-ömürlü ve regülatör proteinlerin y›k›l›m›n› sa¤layarak kat›lmaktad›r. 26S protezomun inhibisyonun heat-shock proteinlerin (örne¤in, Hsp 70 ) sentezini uyard›¤› bilinmesine ra¤men, baz› gruplar 26S protezomun inhibisyonun k›sa bir sürede önemli derecede global protein sentez aktivitesinin de