Bryostatin 1 and phorbol esters are both potent activators of protein kinase C (PKC), although their specific biological effects can differ in many systems. Here, we report that bryostatin 1 activates protein kinase D (PKD), a novel serine/threonine protein kinase, in intact Swiss 3T3 cells and secondary mouse embryo fibroblasts and in COS-7 cells transiently transfected with a PKD expression construct. The dose response of PKD activation induced by bryostatin 1 follows a striking biphasic pattern with maximal activation achieved at a concentration of 10 nM. Higher concentrations of bryostatin 1 (100 nM) reduced PKD activation induced by phorbol 12,13-dibutyrate to levels stimulated by bryostatin 1 alone. Bryostatin 1-induced PKD activation was markedly attenuated by treatment of cells with the PKC inhibitors bisindolylmaleimide I and Ro 31-8220. However, these agents did not inhibit PKD activity when added directly to in vitro kinase assays, suggesting that bryostatin 1 stimulates PKD activation through a PKC-dependent pathway in intact cells. Our results raise the possibility that activated PKD in intact cells could mediate some of the multiple biphasic biological responses induced by bryostatin 1.
|Number of pages||6|
|Journal||Journal of Biological Chemistry|
|Publication status||Published - 1997|
Matthews, S. A., Pettit, G. R., & Rozengurt, E. (1997). Bryostatin 1 induces biphasic activation of protein kinase D in intact cells. Journal of Biological Chemistry, 272(32), 20245-50. http://intl.jbc.org/content/272/32/20245.full.pdf+html?sid=e9eb979d-fda3-439a-ab5a-11e7894f18f0