Frawley, Dean and Karahoda, Betim and Bayram, Ozlem Sarikaya and Bayram, Ozgur (2018) The HamE scaffold positively regulates MpkB phosphorylation to promote development and secondary metabolism in Aspergillus nidulans. Scientific Reports, 8 (16588). ISSN 2045-2322

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Abstract

Mitogen-activated protein kinase (MAPK) pathways are conserved signalling cascades in eukaryotes which regulate a myriad of processes in fungi from sexual reproduction to stress responses. These pathways rely on recruitment of three kinases on a scaffold protein to facilitate efficient kinase phosphorylation and subsequent downstream signalling to the nucleus. The model filamentous fungus Aspergillus nidulans utilises a MAPK pathway termed the pheromone module to regulate both development and secondary metabolism. This complex consists of the MAP3K (SteC), MAP2K (MkkB), MAPK (MpkB) and adaptor protein SteD. To date, there has been no scaffold protein identified for this MAPK pathway. In this study, we characterised a protein termed HamE, which we propose as a scaffold that regulates kinase phosphorylation and signalling in the pheromone module. Mass spectrometry analysis and BIFC experiments revealed that HamE physically interacts with both MkkB and MpkB and transiently interacts with SteC. Deletion of hamE or any of the pheromone module kinases results in reduced sporulation and complete abolishment of cleistothecia production. Mutants also exhibited reductions in expression of secondary metabolite gene clusters, including the velvet complex and sterigmatocystin genes. HamE acts as a positive regulator of MpkB phosphorylation, allowing for HamE to subsequently regulate development and secondary metabolism.

Item Type:	Article
Additional Information:	© The Author(s) 2018. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
Keywords:	HamE scaffold; MpkB phosphorylation; secondary metabolism; Aspergillus nidulans;
Academic Unit:	Faculty of Science and Engineering > Biology
Item ID:	10998
Identification Number:	https://doi.org/10.1038/s41598-018-34895-6
Depositing User:	Ozgur Bayram
Date Deposited:	29 Aug 2019 13:58
Journal or Publication Title:	Scientific Reports
Publisher:	Nature Publishing Group
Refereed:	Yes
URI:
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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