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Use of an activation‐specific probe to show that Rap1A and Rap1B display different sensitivities to activation by forskolin in Rat1 cells
Author(s) -
McPhee Ian,
Houslay Miles D,
Yarwood Stephen J
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01762-2
Subject(s) - forskolin , rolipram , creb , chemistry , microbiology and biotechnology , protein kinase a , phosphorylation , gtpase , phosphodiesterase inhibitor , phosphodiesterase , biology , biochemistry , in vitro , enzyme , transcription factor , gene
Rap1A and Rap1B are small GTPases of the Ras superfamily whose activation can be measured using a probe that interacts specifically with the GTP‐bound forms of Rap1A and Rap1B. Using this procedure we demonstrate that the cyclic AMP‐elevating agent forskolin activates both Rap1A and Rap1B in Rat1 cells. Whilst the protein kinase A inhibitor H89 ablated the ability of forskolin to cause cAMP response element binding protein (CREB) phosphorylation in Rat1 cells, it did not affect the ability of forskolin to activate either Rap1A and Rap1B. Forskolin differentially activated Rap1A and Rap1B isoforms in a time‐ and dose‐dependent manner. The cAMP‐specific type 4 family phosphodiesterase inhibitor rolipram potentiated the rate of activation of both Rap1A and Rap1B by forskolin challenge of Rat1 cells. Challenge of Rat1 cells with rolipram alone was able to elicit the phosphorylation of CREB but not activation of either Rap1A or Rap1B.