VelB/VeA/LaeA Complex Coordinates Light Signal with Fungal Development and Secondary Metabolism

Abstract

European temperate forests (such as to tropical forests or to plant species other than trees). Moreover, if seed-dispersing animals are as crucial to the persistence of plants as this and other studies suggest (28, 29), then the combination of habitat loss with direct and indirect removal of animals, to which many of the world's most diverse forests are subject, is likely to have more drastic effects than either perturbation alone. In these circumstances, animaldispersed species might be more, not less, sensitive to habitat loss. This points to the maintenance of the network of plant-animal interactions as a cornerstone of conservation policy and to the need for more studies of species responses to habitat loss. Differentiation and secondary metabolism are correlated processes in fungi that respond to light. In Aspergillus nidulans, light inhibits sexual reproduction as well as secondary metabolism. We identified the heterotrimeric velvet complex VelB/VeA/LaeA connecting light-responding developmental regulation and control of secondary metabolism. VeA, which is primarily expressed in the dark, physically interacts with VelB, which is expressed during sexual development. VeA bridges VelB to the nuclear master regulator of secondary metabolism, LaeA. Deletion of either velB or veA results in defects in both sexual fruiting-body formation and the production of secondary metabolites.

Fungal S-adenosylmethionine synthetase and the control of development and secondary metabolism in Aspergillus nidulans

“…SasA interaction to other proteins was analyzed by tandem affinity purification (TAP), which allows identifying large relatively stable protein complexes (Bayram et al, 2008;Gavin et al, 2002). This might include proteins which only indirectly interact with SasA if several proteins of the same metabolic or developmental pathway form large complexes.…”

“…TAP experiments were performed as described previously (Bayram et al, 2008) with the TAP-tagged protein strain and the untagged wild type strain as control. In addition to the standard protocol, modified purifications were performed.…”

“…Tryptic peptides were extracted and identified using reversed-phase liquid chromatography coupled with an LCQ DecaXP mass spectrometer (ThermoElectron Corp., San Jose, CA) equipped with a nanoelectrospray ion source (Bayram et al, 2008).…”

“…Light is sensed by photoreceptors that transmit the signal to recipients like the velvet regulators. In the dark, the velvet protein VeA is transported together with the second velvet-like protein VelB into the nucleus, where they can form together with the putative methyltransferase LaeA the trimeric VelB-VeA-LaeA complex which coordinates sexual development and secondary metabolism (Bayram and Braus, 2011;Bayram et al, 2008). A. nidulans LaeA is required for secondary metabolite expression of the sterigmatocystin (ST) or penicillin clusters (Bok and Keller, 2004;Bok et al, 2006).…”

Quantitative proteomics reveals the mechanism and consequence of gliotoxin-mediated dysregulation of the methionine cycle in Aspergillus niger

“…Relevantly, it has been observed that the production of CAZymes and proteases depends on functional regulators BcVEL1 and BcLAE1, in Botrytis cinerea, which are the A. nidulans orthologs of VeA and the SAM-dependent methyltransferase LaeA, respectively [55]. In A. nidulans, VeA and LaeA form a trimeric complex with another member of the velvet protein family, VelB, and this complex is responsible for the regulation of secondary metabolism and development [56]. Apart from functionality in secondary metabolism, LaeA in A. nidulans also controls expression of carbohydrate metabolism enzymes such as Hülle cell specific α-mutanase, which is involved in establishment of fully mature fruiting bodies [57].…”