Involvement of AAA ATPase AipA in endocytosis of the arginine permease AoCan1 depending on AoAbp1 in Aspergillus oryzae. Issue 2 (February 2022) - Hiasa, Reiko
Abstract: AAA ATPases widely exist in many organisms and function in various organelles. However, there is little information about AAA ATPase functioning in endocytosis. In Aspergillus oryzae, we previously discovered a putative AAA ATPase AipA that would be involved in endocytosis. Here, we further examined the function of AipA and AoAbp1 in endocytosis using enhanced green fluorescent protein (EGFP)-tagged arginine permease AoCan1 as an endocytic marker. In the Δ aipA strain, endocytosis of AoCan1-EGFP was more facilitated than the control strain, suggesting that AipA negatively regulates endocytosis. In contrast, in the Δ Aoabp1 strain, endocytosis of AoCan1-EGFP was delayed compared with the control strain, suggesting that AoAbp1 positively functions in endocytosis. In addition, in the Δ aipA Δ Aoabp1 strain, endocytosis of AoCan1-EGFP was delayed. AipA localized at the endocytic collar of the hyphal tip, only in the presence of AoAbp1, suggesting AipA functions downstream of AoAbp1 in endocytosis. Moreover, we investigated the aipA -overexpressing strain, and found that endocytosis of AoCan1-EGFP was inhibited. Furthermore, we examined strains expressing aipA K542A or aipA E596Q, which decreased ATPase activity, in the backgrounds of complementation or overexpression, respectively, and found that AoCan1-EGFP endocytosis was promoted. These results suggested that AAA ATPase activity of AipA is important for its function in endocytosis. Highlights: AipA, a putative AAA ATPase, negatively regulates endocytosis in Aspergillus oryzae. AoAbp1 positively functions in endocytosis of the arginine permease AoCan1. Localization of AipA is dependent on AoAbp1. AipA functions downstream of AoAbp1 in endocytosis of AoCan1. AAA ATPase activity of AipA is important for endocytosis of AoCan1.