CIKS (for connection to IKK and SAPK/JNK), also called Act1 (for NF-kB activator 1), is a novel protein that associates with and activates IKK (IkB kinase). CIKS/Act1 also activates ATF (activating transcription factor) and AP-1 (activator protein 1) throμgh Jun kinase (JNK). CIKS/Act1 is ubiquitously expressed in human tissues.