Functional analysis of predicted DHHC cysteine-rich domain palmitoyl acyltransferase AkrA/ SidR in Aspergilli

Ref ID: 19310

Author:

Yuanwei Zhang, Jinxing Song, Lina Gao, Qingqing Zheng, Ling Lu

Author address:

Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology
Research Center for Microbiology; College of Life Sciences, Nanjing Normal University, Nanjing, 210023,
China

Full conference title:

Asian Mycological Congress 2013 and the 13th International Marine and Freshwater Mycology Symposium

Date: 19 August 2014

Abstract:

Protein palmitoylation is a post-translational modification process that is important in regulation
of membrane-protein interactions and intracellular protein stability. In mammalian cells, the Golgi-specific
zinc finger protein palmitoyl acyltransferase mediates the palmitoylation and posttranslational
modification of many protein substrates. However, the machinery as well as their components involved in
protein palmitoylation has remained elusive in Aspergilli. In this study, human palmitoyl acyltransferases
homologs AkrA in Aspergillus nidulans and SidR in Aspergillus fumigatus have been characterized
respectively using conditional and null deletion mutants. Notably, both of AkrA and SidR contain five
predicted transmembrane domains that possibly are reminiscent of the membrane receptor or transporter.
In addition, either of AkrA or SidR possesses a cytoplasmic DHHC cysteine-rich domain at the
C-terminus, which may confer palmitoyl acyltransferase activity. Moreover, deletion or depletion akrA or
sidR showed significantly smaller colony sizes, and the remarkably reduction of conidiospores under the
low-calcium condition. Interestingly, this growth defect can be significantly suppressed by adding
extracellular calcium, suggesting that hyphal growth and conidiation depends on the function of
AkrA/SidR when strains faced with limited extracellular calcium. Most importantly, the defect of AkrA
displayed a significant hyper-susceptibility to the azole drug -Itraconazole or Voriconazole but showed
the more resistance to cell wall-perturbing agents. These findings suggest that AkrA or SidR may
represent a viable and completely unexplored avenue to be a fungicide target in the Aspergilli. Ongoing
studies will focus on how AkrA/SidR functions by affecting the protein palmitoylation to regulate calcium
signaling pathway and the resistance to azole.

Abstract Number: NULL

Conference Year: 2013

Link to conference website: NULL

New link: NULL

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