protein kinase C conserved region 1 (C1 domain) found in kinase suppressor of Ras 1 (KSR1) and similar proteins
KSR1 functions as a transducer of TNFalpha-stimulated C-Raf activation of ERK1/2 and NF-kB. Detected activity of KSR1 is cell type specific and context dependent. It is inactive in normal colon epithelial cells and becomes activated at the onset of inflammatory bowel disease (IBD). Similarly, KSR1 activity is undetectable prior to stimulation by EGF or ceramide in COS-7 or YAMC cells, respectively. KSR proteins are widely regarded as pseudokinases, however, this matter is up for debate as catalytic activity has been detected for KSR1 in some systems. KSR proteins contain a SAM-like domain, a zinc finger cysteine-rich domain (C1), and a pseudokinase domain. This model describes the C1 domain. The C1 domain is a cysteine-rich zinc binding domain that does not bind DNA nor possess structural similarity to conventional zinc finger domains; it contains two separate Zn(2+)-binding sites.
Jiyao W et al.(2023). "The conserved domain database in 2023.",