Deletion of <i>admB</i> gene encoding a fungal ADAM affects cell wall construction in <i>Aspergillus oryzae</i>

<p>Mammals possess a unique signaling system based on the proteolytic mechanism of a disintegrin and metalloproteinases (ADAMs) on the cell surface. We found two genes encoding ADAMs in <i>Aspergillus oryzae</i> and named them <i>admA</i> and <i>admB</i>. We produced <i>admA</i> and <i>admB</i> deletion strains to elucidate their biological function and clarify whether fungal ADAMs play a similar role as in mammals. The <i>∆admA∆admB</i> and <i>∆admB</i> strains were sensitive to cell wall-perturbing agents, congo red, and calcofluor white. Moreover, the two strains showed significantly increased weights of total alkali-soluble fractions from the mycelial cell wall compared to the control strain. Furthermore, <i>∆admB</i> showed MpkA phosphorylation at lower concentration of congo red stimulation than the control strain. However, the MpkA phosphorylation level was not different between <i>∆admB</i> and the control strain without the stimulation. The results indicated that <i>A. oryzae</i> AdmB involved in the cell wall integrity without going through the MpkA pathway.</p>