The CKI-epsilon Colorimetric Cell-Based ELISA is a convenient, lysate-free, high throughput and sensitive assay kit that can detect CKI-epsilon protein expression profile in cells. The kit can be used for measuring the relative amounts of CKI-epsilon in cultured cells as well as screening for the effects that variuos treatments, inhibitors (ie siRNA or chemicals), or activators have on CKI-epsilon.