You are not currently logged in.
Access JSTOR through your library or other institution:
If You Use a Screen ReaderThis content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Phorbol Ester-Induced Stimulation and Phosphorylation of Adenylyl Cyclase 2
Ofer Jacobowitz and Ravi Iyengar
Proceedings of the National Academy of Sciences of the United States of America
Vol. 91, No. 22 (Oct. 25, 1994), pp. 10630-10634
Published by: National Academy of Sciences
Stable URL: http://www.jstor.org/stable/2366083
Page Count: 5
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preview not available
Adenylyl cyclase 2 was expressed in Sf9 cells by recombinant baculovirus infection. Phorbol 12-myristate 13-acetate (PMA) treatment of cells expressing adenylyl cyclase 2 (AC2) increased basal activity. This increase was blocked by staurosporine, a protein kinase C inhibitor. PMA treatment increased Vmax without affecting Km. Greatest increase in basal activity was seen at physiologically relevant Mg2+ concentrations. PMA treatment did not alter sensitivity to guanine nucleotide stimulatory factor (Gs) but enhanced stimulation at all concentrations of activated Gs α subunit tested. AC2 was tagged at the N terminus with an 8-amino acid epitope. Epitope-tagged AC2 was purified to apparent homogeneity in a single step by using an antiepitope antibody-affinity column. The eluate was resolved by SDS/PAGE. Silver staining of the gel showed a 106-kDa band. The purified protein was recognized by antipeptide antibody against a region common to all mammalian adenylyl cyclases. The epitope-tagged enzyme expressed in Sf9 cells was also stimulated by PMA. When cells were labeled with 32P and treated with PMA, a 3-fold increase in 32P incorporation of purified epitope-tagged AC2 was observed. We conclude that activation of protein kinase C results in phosphorylation and stimulation of AC2, a cell-surface G protein effector enzyme. Thus, covalent modification of cell-surface effectors may provide an independent mode for signal transmission through G protein pathways.
Proceedings of the National Academy of Sciences of the United States of America © 1994 National Academy of Sciences