, 2009a). The apical endocytic recycling OSI-744 model in filamentous fungi has been widely accepted (Steinberg, 2007; Taheri-Talesh et al., 2008; Upadhyay & Shaw, 2008; Abenza et al., 2009; Peñalva, 2010). Notably, in

A. oryzae, endocytosis-deficient hyphae display severe defective growth, suggesting that endocytosis and apical growth are highly linked (Higuchi et al., 2009b). In Aspergillus nidulans, similar localization and functional analyses of endocytic proteins, such as AbpA, AmpA, FimA, and SlaB, the orthologs of S. cerevisiae Abp1p, Rvs167p, Sac6p, and End4p/Sla2p, respectively, have been reported (Araujo-Bazán et al., 2008; Taheri-Talesh et al., 2008; Upadhyay & Shaw, 2008; Hervas-Aguilar & Penalva, 2010). Although novel insights,

this website such as apical endocytic recycling, have been elucidated based on the analyses of ortholog proteins of S. cerevisiae, a more detailed mechanism related to endocytosis in the hyphal tip region has not yet been clarified (Peñalva, 2010). AAA ATPases are conserved from prokaryotes to humans and play roles in various processes such as membrane fusion and protein degradation (White & Lauring, 2007). AAA ATPases contain the ATPase domain at the C-terminus with high homology, but the rest of the regions are not well conserved. Moreover, AAA ATPases form a ring-shaped hexamer with a central pore and the ATPase domain facing inside. In the endocytic pathway, an AAA ATPase Vps4p in S. cerevisiae functions in the disassembly of the ESCRT (endosomal sorting complexes required for transport)-III Rutecarpine complex from the membrane of multivesicular bodies (MVBs) to the cytoplasm (Babst et al., 1997, 1998; Saksena et al., 2009). Although there are several reports on AAA ATPases in many organisms, no protein that functions in endocytosis has been reported so far (White & Lauring, 2007). According to the analyses of endocytic proteins in A. oryzae, the mechanism of endocytosis, which

is characteristic of the organism, seems to exist at the apical region. We, therefore, explored novel components associated with endocytosis by yeast two-hybrid (YTH) screening using an endocytic marker protein AoAbp1, having two SH3 domains at the C-terminal region, which are related to endocytic protein–protein interaction, as bait. Of the candidates obtained by YTH screening, the gene aipA was found, which likely encodes AAA ATPase. The interaction between AipA and AoAbp1 by YTH and in vitro, in vivo localization, and functional analyses using the aipA-overexpressing strain suggested that AipA is a putative AAA ATPase negatively functioning in apical endocytic recycling. The A. oryzae strains used in this study are listed in Table 1. The DNA cloning methods used in this study were described previously (Higuchi et al., 2009b). All plasmids used for A. oryzae transformation in this study were constructed by the MultiSite Gateway System (Invitrogen).