FIGURE 5:

Sec1 is important for cytokinesis. (A) Homology modeling of Sec1 using the crystal structure of human Munc18-2 (PDB: 4cca) as a template. Residues mutated in the sec1-M2 mutant are highlighted in green. (B) The sec1-M2 mutant is temperature sensitive and defective in cell growth at 36°C. Cells were grown on YE5S and YE5S + PB plates for 2 d. (C) Sec1-M2 loses localization on the plasma membrane and accumulates to cytoplasmic puncta after grown at 36°C for 2 h. (D) Mso1 loses localization on the plasma membrane in sec1-M2 cells grown at 36°C for 4 h. (E) Cytoplasmic puncta of Sec1-M2 and Mso1 do not colocalize in sec1-M2 cells grown at 36°C for 2 h. (F, G) Time courses (F) and quantification (G) of Rlc1-tdTomato labeled contractile ring in WT and sec1∆ cells grown at 25°C. The arrows indicate the start (red) and end (white) of ring constriction and the end (yellow) of ring disassembly. Error bars shown are SDs. Bars, 5 µm.