 This function of IKK-α has been shown to be independent of the protein's kinase activity and of the NF-κB pathway.Instead it is thought that IKK-α regulates skin differentiation by acting as a cofactor in the TGF-β / Smad2/3 signaling pathway.The zebrafish homolog of IKK-α has also been shown to play a role in the differentiation of the embryonic epithelium.