Rabbit Anti-Human CUL1 polyclonal antibody for IHC-P. Cullin-1 is a member of the family of human cullin genes (cullin-1, 2, 3, 4a, 4b, and 5) homologous to the s. cerevisiae cdc53 gene. Cullin-1 forms a complex with human p19skp1 and F box protein p45skp2, both of which, together with cdc53, as three subunits, form an ubiquitin ligase controlling proteolysis of G1 cell cycle regulatory proteins. The cullin-1/p19skp1/p45skp2 complex is thought to play a role in the ubiquitination of G1 regulatory proteins.