, 2010). For instance, while the deletion of Pil1 leads to
clustering of the remaining eisosome components, aberrant plasma membrane invaginations and the reduction of the endocytic rate in yeast (Walther et al., 2006), the deletion of Pil1 homologue in A. oryzea, and A. nidulans had no effect on endocytosis (Higuchi et al., 2009; Vangelatos et al., 2010). In view of the important role of Nce102 in eisosome assembly in yeast and the possible involvement in nonclassical export of Linsitinib manufacturer some virulence factors to the cell surface (Nombela et al., 2006), we carried out a gene knock out study to understand the role of Nce102 homologue in the growth and pathogenesis of A. fumigatus. We first identified the gene in fungal genome data base, cloned it, and generated a deletion mutant. The intracellular localization of AfuNce102 was also examined using EGFP-tagged AfuNce102. AfuNce102 deletion mutant showed a clear delay in conidiophore formation at 37 °C and severely affected sporulation at 25 °C. Asexual sporulation is a complex process that requires highly coordinated activity of upstream and central developmental pathways. For instance, FluG pathway contains several upstream developmental activators that can activate an overlapping regulatory pathway containing key
conidiation regulators like brlA and wetA (Etxebeste et al., 2010). In examination of brlA expression levels as the central regulator of conidiation, we did not detect any difference between the parental strain and the AfuNce102 deletion mutant indicating that AfuNce102
may not CH5424802 manufacturer influence brlA expression in A. fumigatus. AfuNce102 does not seem to be related to an extracellular sporulation activating factor (s), which is thought to be a product of fluG gene (D’Souza et al., 2001). This was concluded as the conidiation defect of AfuNce102 deletant was not suppressed when the mutant was grown in the vicinity of the wild type. In addition to the main regulatory pathways, several reports have introduced other key players in sporulation process. For example, Soid-Raggi et al. (2006) have identified a transmembrane flavoprotein, Tmpa, which is necessary for conidiophore formation in A. nidulans, and Li et al. (2007) demonstrated the role of normal sphingolipid metabolism in asexual sporulation. Although the deletion of eisosomal PDK4 proteins, Pil A, PilB, or SurG, in A. nidulans has not changed the growth phenotype, sporulation, or spore survival (Vangelatos et al., 2010), the deletion of Nce102 homologue in A. fumigatus caused abnormal sporulation. The most severe defect in conidiation was observed at 25 °C. This may indicate an additional function for AfuNCE102 in fungal development. It has been proposed that Nce102 can modulate plasma membrane organization through sphingolipid signaling in yeast. The overexpression of Nce102 in yeast can block the inhibitory effect of a sphingolipid synthesis blocker, myriocin, on eisosomes (Frohlich et al., 2009).