Research Resource: Identification of Novel Growth Hormone-Regulated Phosphorylation Sites by Quantitative Phosphoproteomics

Ray, Bridgette N.; Kweon, Hye Kyong; Argetsinger, Lawrence S.; Fingar, Diane C.; Andrews, Philip C.; Carter-Su, Christin

implicated as a grb2 binding site (61) . NHE1 is a sodium/ proton antiporter that catalyzes the exchange of Na Ï© and H Ï© down their concentration gradients. This exchange is important for control of intracellular pH, adhesion, migration, and proliferation. Phosphorylation of Ser707 of NHE1 has been reported to increase the antiporter activity of NHE1 (35) . NDRG1 has been implicated in growth and differentiation and is necessary for p53-induced apoptosis (62) (63) (64) . Phosphorylation of Ser330 (and Thr328) of NDRG1 primes NDRG1 for further phosphorylation by GSK3 (65) and is required for the suppressive effect of NDRG1 on the nuclear factor-B signaling pathway (66) . Finally, ACLY is the primary enzyme responsible for the synthesis of cytosolic acetyl-coenzyme A (CoA) in many tissues. Phosphorylation of ACLY Ser455 by Akt has been shown to activate ACLY (67) .