14-3-3 sigma Adenovirus (Ad-sigma)

14-3-3sigma is a member of the multifunctional 14-3-3 protein family that includes beta, epsilon, gamma, eta, tau, and zeta. They recognize consensus motifs containing Arg-Ser-X-phosphoSer-X-Pro or its derivatives, and are able to bind proteins with phosphorylated serine or threonine. Through interactions with other proteins, 14-3-3 proteins is involved in controlling a wide range of regulatory processes, such as mitogenic signal transduction, apoptotic cell death, and cell cycle control. They can function as allosteric cofactors to alter the catalytic activity or conformational state of target proteins, such as PKC, ExoS ADP-ribosyltransferase, and tyrosine and tryptophan hydroxylases. They may also act as steric regulators to prevent their protein ligands from interacting with other cellular components, hence, influence intracellular localization or complex formation. Dimeric 14-3-3 can bind two target proteins simultaneously to operate as a scaffold protein to induce protein-protein interactions. 14-3-3sigma functions as a p53-regulated inhibitor of G2/M progression and plays a key role in maintaining G2-arrest upon DNA damage in certain cancer cells, such as the colorectal cells. They are primarily found in the cytoplasm and may be required to sequester mitotic activators cyclin B1 and cdc2 in cytoplasm. Overexpression of 14-3-3sigma can induce G2 arrest and deletion of 14-3-3sigma can lead to mitotic catastrophe upon DNA damage. This adenovirus contain Ad-σ. Reference: Hermeking H., et al., Mol Cell. 1997 Dec;1 (1) :3-11.