Phosphorylation of CnYpd1 from a heterologous phosphodonor. The HK and RR domains from a heterologous donor, Sln1 from S. cerevisiae (Sln1-HKR1), were used to phosphorylate CnYpd1. ScSln1-HKR1 was autophosphorylated using 0.1 μM γ- 32 P-labeled ATP (lane 1). ScSln1-HKR1 was incubated with CnYpd1 alone (lane 2) or with ScSsk1-R2 (lane 3), CnYpd1-H138Q alone (lane 4) or with ScSsk1-R2 (lane 5).