Busch Silke, Schwier Elke U, Nahlik Krystyna, Bayram Ozür, Helmstaedt Kerstin, Draht Oliver W, Krappmann Sven, Valerius Oliver, Lipscomb William N, Braus Gerhard H
Institut für Mikrobiologie und Genetik, Georg-August-Universität, Grisebachstrasse 8, D-37077 Göttingen, Germany.
Proc Natl Acad Sci U S A. 2007 May 8;104(19):8089-94. doi: 10.1073/pnas.0702108104. Epub 2007 Apr 30.
Fruit body formation in filamentous fungi is a complex and yet hardly understood process. We show here that protein turnover control is crucial for Aspergillus nidulans development. Deletion of genes encoding COP9 signalosome (CSN) subunits 1, 2, 4, or 5 resulted in identical blocks in fruit body formation. The CSN multiprotein complex controls ubiquitin-dependent protein degradation in eukaryotes. Six CSN subunits interacted in a yeast two-hybrid analysis, and the complete eight-subunit CSN was recruited by a functional tandem affinity purification tag fusion of subunit 5 (CsnE). The tagged CsnE was unable to recruit any CSN subunit in a strain deleted for subunit 1 or subunit 4. Mutations in the JAMM metalloprotease core of CsnE resulted in mutant phenotypes identical to those of csn deletion strains. We propose that a correctly assembled CSN including a functional JAMM links protein turnover to fungal sexual development.
丝状真菌子实体的形成是一个复杂但却鲜为人知的过程。我们在此表明，蛋白质周转控制对构巢曲霉的发育至关重要。编码COP9信号体（CSN）亚基1、2、4或5的基因缺失导致子实体形成出现相同的障碍。CSN多蛋白复合物控制真核生物中泛素依赖性蛋白质降解。在酵母双杂交分析中，六个CSN亚基相互作用，并且通过亚基5（CsnE）的功能性串联亲和纯化标签融合招募了完整的八亚基CSN。在缺失亚基1或亚基4的菌株中，带有标签的CsnE无法招募任何CSN亚基。CsnE的JAMM金属蛋白酶核心中的突变导致与csn缺失菌株相同的突变表型。我们提出，一个正确组装的包括功能性JAMM的CSN将蛋白质周转与真菌有性发育联系起来。
