Figure 1.

KSR1 binds directly to calmodulin in a Ca²⁺-regulated manner.A, GST-Sepharose (GST) or calmodulin-Sepharose (CaM) was incubated with 500 ng of purified His-KSR1 in the presence of 1 mM Ca²⁺ or 1 mM EGTA. After washing the beads, attached proteins were resolved by SDS-PAGE and western blotting. Blots were probed with anti-KSR1 and anti-GST antibodies. Input is purified KSR1 not subjected to pull-down. The data are representative of two independent experiments. B, in total, 1 mg protein lysate prepared from KSR1+/+ MEFs in the presence of 1 mM Ca²⁺ or 1 mM EGTA was incubated with GST-Sepharose (GST) or calmodulin-Sepharose (CaM) beads. Samples were processed by SDS-PAGE and western blotting. Blots were probed with anti-KSR1 and anti-calmodulin (CaM) antibodies. Input is 20 μg lysate not subjected to pull-down. An empty lane is designated by (#). The data are representative of three independent experiments. The positions of migration of molecular mass markers are indicated on the left.