Functional Spliceosome Associated Protein c (fSAPc)

Cactin, a conserved protein that interacts with the Drosophila IkappaB protein cactus and modulates its function. Rel transcription factors function in flies and vertebrates in immunity and development. Although Rel proteins regulate diverse processes, the control of their function is conserved.

Like the other components of this pathway, Cactin is evolutionarily conserved. Over-expression of cactin in a cactus(A2) heterozygous background results in the enhancement of the cactus phenotype. Both the embryonic lethality and ventralization are strongly increased, suggesting that cactin functions in the Rel pathway controlling the formation of dorsal-ventral embryonic polarity.