A. Neither xDsh nor mPer1 bind strongly to CKIα→ε.

GST, GST-CKIε (partially purified) or GST- CKIα→ε, was bound to glutathione sepharose and incubated with ³⁵S-labeled xDsh or mPer1. (B) GST, GST-CKIε, or GST- CKIα→ε I283N/T287R, was bound to glutathione sepharose and incubated with ³⁵S-labeled xDsh or mPer1. The bar graphs represent quantification of three independent experiments. Values are normalized against the amount of protein bound to GST-CKIε.