Constitutive Photomorphogenesis Protein 1 (COP1)

Mouse Cop1 contains an N-terminal RING finger domain, a coiled-coil domain, and C-terminal WD40 repeats. A cytoplasmic localization signal is located in the region that connects and overlaps the RING finger and coiled-coil domains. Both mouse and human COP1 have a central bipartite nuclear localization signal (NLS).The deduced protein contains 771 amino acids. EST database analysis indicated that mammalian COP1 is widely expressed in tissues and organs in both embryos and adults, and COP1 homologs were identified in several different species. Northern blot analysis detected widespread expression of COP1, with highest levels in testis, placenta, skeletal muscle, and heart. Western blot analysis detected little to no endogenous COP1 in several cell lines and primary cultures, suggesting low total protein levels.