An eight-subunit COP9 signalosome with an intact JAMM motif is required for fungal fruit body formation.
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.
Busch
Silke
S
Institut für Mikrobiologie und Genetik, Georg-August-Universität, Grisebachstrasse 8, D-37077 Göttingen, Germany.
Schwier
Elke U
EU
Nahlik
Krystyna
K
Bayram
Ozür
O
Helmstaedt
Kerstin
K
Draht
Oliver W
OW
Krappmann
Sven
S
Valerius
Oliver
O
Lipscomb
William N
WN
Braus
Gerhard H
GH
D020816:Amino Acid Motifs; D001233:Aspergillus nidulans / Q000235:genetics / Q000254:growth & development*; D000075686:COP9 Signalosome Complex; D016681:Genome, Fungal; D046912:Multiprotein Complexes / Q000737:chemistry* / Q000502:physiology; D010447:Peptide Hydrolases / Q000737:chemistry* / Q000502:physiology; D010641:Phenotype; D021122:Protein Subunits
D046912:Multiprotein Complexes; D021122:Protein Subunits; D010447:Peptide Hydrolases; D000075686:COP9 Signalosome Complex