F-box receptor mediated control of substrate stability and subcellular location organizes cellular development of Aspergillus nidulans

Abstract

Fungal growth and development are coordinated with specific secondary metabolism. This coordination requires 8 of 74 F-box proteins of the filamentous fungus Aspergillus nidulans. F-box proteins recognize primed substrates for ubiquitination by Skp1-Cul1-Fbx (SCF) E3 ubiquitin RING ligases and degradation by the 26S proteasome. 24 F-box proteins are found in the nuclear fraction as part of SCFs during vegetative growth. 43 F-box proteins interact with SCF proteins during growth, development or stress. 45 F-box proteins are associated with more than 700 proteins that have mainly regulatory roles. This corroborates that accurate surveillance of protein stability is prerequisite for organizing multicellular fungal development. Fbx23 combines subcellular location and protein stability control, illustrating the complexity of F-box mediated regulation during fungal development. Fbx23 interacts with epigenetic methyltransferase VipC which interacts with fungal NF-κB-like velvet domain regulator VeA that coordinates fungal development with secondary metabolism. Fbx23 prevents nuclear accumulation of methyltransferase VipC during early development. These results suggest that in addition to their role in protein degradation, F-box proteins also control subcellular accumulations of key regulatory proteins for fungal development.

Fungal COP9 signalosome assembly requires connection of two trimeric intermediates for integration of intrinsic deneddylase

“…Fungal CSN senses and inactivates substrateless SCF E3 ubiquitin ligases and initiates F-box receptor exchanges, allowing degradation of different proteins ( 11 ). This includes CSN control and exchange of nuclear A. nidulans F-box proteins for anticipated stress and development, which can associate with regulatory proteins ( 12 ). Fungal F-box proteins are involved in virulence ( 61 ) and increased cellular deneddylation activity is associated with human cancers ( 13 ).…”

“…During vegetative growth 24 F-box proteins are present as part of SCFs in the nuclear fraction. They are required for anticipated stress conditions and often associate with regulatory proteins ( 12 ). Dynamic cycles of cullin-RING ligase neddylation–deneddylation by Cand1/A and CSN allow sequential labeling of different substrates and promote multicellular development.…”

The KdmB-EcoA-RpdA-SntB (KERS) chromatin regulatory complex controls development, secondary metabolism and pathogenicity in Aspergillus flavus

“…Isolation and preparation of GFP and HA fusion proteins for mass spectrometry analysis was performed as explained in detail ( Helmstaedt et al, 2008 ; Sarikaya Bayram et al, 2022 ; Sarikaya Bayram et al, 2019 ). GFP and HA experiments were performed from two independent biological replicates.…”

An Anatomy of Fungal Eye: Fungal Photoreceptors and Signalling Mechanisms

“…These highly branched mycelia can differentiate into asexual or sexual organs, which finally lead to asexual or sexual spores. Along with these developmental processes, fungi also coordinate their primary and secondary metabolism [11,20] whereby production of certain pigments and bioactive metabolites is also associated with development [21,22].…”