FIGURE 5.

Sub-cellular localization patterns of the pheromone module proteins in vivo. (A) Sub-cellular localization of SteC-GFP. Strains from panels A–D were incubated at 30°C for various durations in 400 μL of liquid GMM, containing appropriate supplements. “BF” (brightfield images). “GS” (grayscale images). To visualize the nuclei, DAPI staining was performed. White arrows depict the accumulation of fusion protein in the nuclei. “HT” refers to accumulation of protein at hyphal tips. (B) Sub-cellular localization of MkkB-GFP. (C) Sub-cellular localization of MpkB-GFP. (D) Sub-cellular localization of SteD-GFP. (E) Sub-cellular localization of HamE-HA. The HamE-HA strain was inoculated (5 × 10³ spores) on sterile coverslips, covered in 450 μL of Sabouraud media, containing supplements. This strain were left to incubate at 30°C for 16 h. (F) Schematic model of the pheromone module in A. fumigatus. MkkB, MpkB, and HamE localize to the hyphal tips. These three proteins interact with the SteC-SteD dimer in the cytoplasm to form a pentameric complex which results in MpkB activation and transduction of a signal downstream to the nucleus. MpkB translocates into the nucleus, where it presumably interacts with transcription factors to positively regulate asexual sporulation, vegetative growth, stress responses and production of various SMs. “P” represents phosphate groups.