FIGURE 3.

Rac is required for Erk activation. A, YT cells were preincubated with the Rac inhibitor EHT 1864 and then stimulated with C. neoformans for the indicated times. YT cells were then lysed and immunoblotted for pErk and Erk. The immunoblot is representative of two experiments. B, YT cells were preincubated with various concentrations of Rac inhibitor II. YT cells were then stimulated with Cryptococcus and lysed. The lysates were immunoblotted for pErk and Erk. The immunoblot is representative of two experiments. C, YT transfected with nontargeting or Rac1 specific siRNA. Transfected YT cells were stimulated with Cryptococcus, and levels of pErk and Erk were determined by immunoblots. The immunoblot is representative of three experiments. YT, unstimulated YT cells alone; C+YT, YT cells stimulated with Cryptococcus; NT, nontargeting