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Cell‐free heterologous desensitization of adenylyl cyclase in S49 lymphoma cell membranes mediated by cAMP‐dependent protein kinase
Author(s) -
Kunkel Mark W.,
Friedman Jacqueline,
Shenolikar Shirish,
Clark Richard B.
Publication year - 1989
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.3.9.2545497
Subject(s) - adenylyl cyclase , homologous desensitization , protein kinase c , forskolin , desensitization (medicine) , heterologous , gs alpha subunit , adcy9 , adcy10 , protein kinase a , chemistry , medicine , microbiology and biotechnology , biology , endocrinology , receptor , signal transduction , biochemistry , kinase , gene
We have examined the cell‐free heterologous desensitization of adenylyl cyclase in plasma membrane preparations from S49 wild‐type (WT) and kin − cells (which lack cAMP‐dependent protein kinase) incubated with purified catalytic subunit of cAMP‐dependent protein kinase (cA·PKc). cA·PK c caused a rapid ( t 1/2 = 40 s) decrease in the hormone responsiveness of adenylyl cyclase in the WT membrane preparations that mimicked the intact cell heterologous desensitization; that is, there was an increase in the K act for both epinephrine and prostaglandin E 1 (PGE 1 ) stimulations of adenylyl cyclase induced at the receptor level because neither forskolin‐ nor NaF‐stimulated activity was affected. The desensitization was independent of agonist occupancy of the receptor, and the effects were blocked both by the active fragment (amino acids 5‐22) of the specific inhibitor of cA · PK and by p[NH]ppA. cA · PK c treatment of kin − membranes resulted in a heterologous desensitization that resembled the effects on WT adenylyl cyclase, with the exception that forskolinstimulated activity was also reproducibly decreased by 24%. cA·PK c had no effect on WT membranes isolated from cells that had previously undergone maximal heterologous desensitization during treatment with 10 μM forskolin. In contrast, cA · PK c ‐induced heterologous desensitization of kin − membranes was additive with the epinephrine‐induced homologous desensitization of intact cells. Cell‐free desensitizations were reversed by incubation of membranes with cA·PK c and ADP, conditions that drive the kinase reaction backward. The similarities of our cell‐free cA · PK c ‐mediated heterologous desensitization of adenylyl cyclase with the intact cell desensitization support our hypothesis that heterologous desensitization of the WT lymphoma cells is mediated by cA·PK via a mechanism independent of homologous desensitization.—K unkel , M. W.; F riedman , J.; S henolikar , S.; C lark , R. B. Cell‐free heterologous desensitization of adenylyl cyclase in S49 lymphoma cell membranes mediated by cAMP‐dependent protein kinase. FASEB J. 3: 2067‐2074; 1989.