Comprehensive Analysis of <named-content content-type="genus-species">Aspergillus nidulans</named-content> PKA Phosphorylome Identifies a Novel Mode of CreA Regulation
Liliane F. C. Ribeiro,
Cynthia Chelius,
Karthik R. Boppidi,
Nisha S. Naik,
Simin Hossain,
Jessica J. J. Ramsey,
Jyothi Kumar,
Lucas F. Ribeiro,
Marc Ostermeier,
Bao Tran,
Young Ah Goo,
Leandro J. de Assis,
Mevlut Ulas,
Ozgur Bayram,
Gustavo H. Goldman,
Stephen Lincoln,
Ranjan Srivastava,
Steven D. Harris,
Mark R. Marten
Affiliations
Liliane F. C. Ribeiro
Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County (UMBC), Baltimore, Maryland, USA
Cynthia Chelius
Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County (UMBC), Baltimore, Maryland, USA
Karthik R. Boppidi
Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County (UMBC), Baltimore, Maryland, USA
Nisha S. Naik
Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County (UMBC), Baltimore, Maryland, USA
Simin Hossain
Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County (UMBC), Baltimore, Maryland, USA
Jessica J. J. Ramsey
Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County (UMBC), Baltimore, Maryland, USA
Jyothi Kumar
Center for Plant Science Innovation, University of Nebraska, Lincoln, Nebraska, USA
Lucas F. Ribeiro
Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA
Marc Ostermeier
Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA
Bao Tran
Mass Spectrometry Center, University of Maryland School of Pharmacy, Baltimore, Maryland, USA
Young Ah Goo
Mass Spectrometry Center, University of Maryland School of Pharmacy, Baltimore, Maryland, USA
Leandro J. de Assis
Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
Mevlut Ulas
Department of Biology, Maynooth University, Maynooth, County Kildare, Ireland
Ozgur Bayram
Department of Biology, Maynooth University, Maynooth, County Kildare, Ireland
Gustavo H. Goldman
Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, CEP 14040-903, São Paulo, Brazil
Stephen Lincoln
Chemical & Biomolecular Engineering Department, University of Connecticut, Storrs, Connecticut, USA
Ranjan Srivastava
Chemical & Biomolecular Engineering Department, University of Connecticut, Storrs, Connecticut, USA
Steven D. Harris
Center for Plant Science Innovation, University of Nebraska, Lincoln, Nebraska, USA
Mark R. Marten
Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County (UMBC), Baltimore, Maryland, USA
ABSTRACT In filamentous fungi, an important kinase responsible for adaptation to changes in available nutrients is cyclic AMP (cAMP)-dependent protein kinase (protein kinase A [PKA]). This kinase has been well characterized at a molecular level, but its systemic action and direct/indirect targets are generally not well understood in filamentous fungi. In this work, we used a pkaA deletion strain (ΔpkaA) to identify Aspergillus nidulans proteins for which phosphorylation is dependent (either directly or indirectly) on PKA. A combination of phosphoproteomic and transcriptomic analyses revealed both direct and indirect targets of PKA and provided a global perspective on its function. One of these targets was the transcription factor CreA, the main repressor responsible for carbon catabolite repression (CCR). In the ΔpkaA strain, we identified a previously unreported phosphosite in CreA, S319, which (based on motif analysis) appears to be a direct target of Stk22 kinase (AN5728). Upon replacement of CreA S319 with an alanine (i.e., phosphonull mutant), the dynamics of CreA import to the nucleus are affected. Collectively, this work provides a global overview of PKA function while also providing novel insight regarding significance of a specific PKA-mediated phosphorylation event. IMPORTANCE The cyclic AMP (cAMP)-dependent protein kinase A (PKA) signaling pathway is well conserved across eukaryotes, and previous work has shown that it plays an important role in regulating development, growth, and virulence in a number of fungi. PKA is activated in response to extracellular nutrients and acts to regulate metabolism and growth. While a number of components in the PKA pathway have been defined in filamentous fungi, current understanding does not provide a global perspective on PKA function. Thus, this work is significant in that it comprehensively identifies proteins and functional pathways regulated by PKA in a model filamentous fungus. This information enhances our understanding of PKA action and may provide information on how to manipulate it for specific purposes.
