FIG. 4.

Analysis of septin complexes in wild-type and mutant strains. (A and B) Septin complexes are disrupted at 37°C in GTP-binding mutants. Strains were grown to mid-log phase at 23°C and shifted to 37°C for 2 h. Lysates from wild-type and cdc11 or cdc3 mutant strains (A) or cdc10 or cdc12 mutant strains (B) were prepared, and total protein, or immunoprecipitates obtained with the indicated antibodies, were separated by SDS-PAGE and immunoblotted to detect Cdc3p, Cdc10p, Cdc11p, or Cdc12p. Strains are as described for Fig. 1, with M-2332 used as the wild-type strain. The asterisk indicates the immunoglobulin heavy chain, which migrates just above Cdc12p. (C) Septin complexes are partially disrupted at semipermissive temperatures. MATa strains were arrested with α-factor at 23°C, shifted to the indicated temperature for 20 min, and released from cell cycle arrest at the indicated temperature. At 40 min after release, lysates were prepared and septin complex formation assayed as described above. Strains are as for Fig. 1, with M-2332 used as the wild-type strain.