- Physical interactions between phospholamban and sarco(endo)plasmic reticulum Ca2+-ATPases are dissociated by elevated Ca2+, but not by phospholamban phosphorylation, vanadate, or thapsigargin, and are enhanced by ATP. Asahi, M., McKenna, E., Kurzydlowski, K., Tada, M., MacLennan, D.H. J. Biol. Chem. (2000)