Analysis of the C‐terminal domain of MtlA and its role in cell wall metabolism in the fungus Aspergillus nidulans

Abstract

The Mid2‐like protein MtlA is a putative sensor that affects cell wall integrity in the filamentous fungus Aspergillus nidulans. Plasmid‐based, overexpression of MtlA can suppress the calC2 mutation in the A. nidulans orthologue of protein kinase C (PkcA), which results in hypersensitivity to the chitin‐binding agent Calcofluor White. In filamentous fungi, as in yeasts, hypersensitivity to CFW correlates with defects in cell wall integrity. MtlA is predicted to have a single transmembrane domain, an extracellular domain rich in serine and threonine amino acids residues, and a C‐terminal domain of 59 amino acids. A MtlA ‐GFP hybrid localizes to the plasma membrane of vegetative hyphae. In the cell wall integrity pathway in yeast, the C‐terminal domain of the stress receptors, Wsc1 and Mid2, have been shown to play an important role in the signal transduction pathway. We have shown that the C‐terminal domain of MtlA plays an important role in cell wall integrity. We have created and analyzed C‐terminal truncation mutants of MtlA and have shown that complete removal of the C‐terminal domain obliterates its function. We have also shown that amino acids 241–251 are critical for the function of MtlA. Site directed mutagenesis of key amino acids will be elucidated.Support or Funding InformationRhodes CollegeNational Science FoundationThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.