Developmental regulation by constitutive activation and inactivation of MpkB MAPK pathway in Aspergillus nidulans

Sang-Cheol Juna, Kwang-Yeop Jahngb, Jong-Hwa Kimc and Kap-Hoon Hanc

Author address: 

aInstitute for Genetic Engineering, Chonbuk National University, Jeonju, South Korea bDepartment of Life Sciences, Chonbuk National University, Jeonju, South Korea cDepartment of Pharmaceutical Engineering, Woosuk Univ, Wanju, Jeonbuk, South Korea


The mpkB gene is a member of the multiple MAPK pathways in Aspergillus nidulans. The MpkB has been

known to play a key role in the asexual and sexual development and secondary metabolite production.

The MAPK kinase MkkB can be phosphorylated at Ser218 and Thr222 residues within the activation loop

site by SteC MAPKK kinase and consequently, activates MpkB by phosphorylating at threonine and

tyrosine residues of MpkB in A. nidulans. By introducing negatively charged (aspartic acid) or non-polar

(proline and lysine) residues that may mimic the effect of phosphorylation at positions 218 and 222 in

MkkB, we constructed mutants which constitutively phosphorylate MpkB MAPK and constitutively nonphosphorylate

MpkB MAPK. Expression of the constitutively activated MkkB in A. nidulans led to the

hyper-activation of MpkB MAPK and resulted in a great elevation of sexual development, while asexual

sporulation was remarkably reduced. In contrast, constitutively inactivated MkkB mutant could not

produce sexual organs, while asexual sporulation and sterigmatocystin production were normally

processed. Differential expression pattern of proteins among these mutants were analyzed by using the

2D proteomic analysis, which revealed that expression level of 375 spots are significantly different.


abstract No: 


Full conference title: 

The Fourteenth International Aspergillus Meeting, Asilomar Conference Center, Pacific Grove, CA, USA
    • Asperfest 14 (2017)