Compartmentalized cAMP signalling in regulated exocytic processes in non-neuronal cells.
Cyclic adenosine monophosphate (cAMP) is a central second messenger controlling a plethora of vital functions. Studies of cAMP dynamics in living cells have revealed markedly inhomogeneous concentrations of the second messenger in different compartments. Moreover, cAMP effectors such as cAMP-dependent protein kinase (PKA) and cAMP-activated GTP-exchange factors (Epacs) are tethered to specific cellular sites. Both the tailoring of cAMP concentrations, and the activities of cAMP-dependent signalling systems at specific cellular locations are prerequisites for most, if not all, cAMP-dependent processes. This review focuses on the role of compartmentalized cAMP signalling in exocytic processes in non-neuronal cells. Particularly, the insertion of aquaporin-2 into the plasma membrane of renal principal cells as an example for a cAMP-dependent exocytic process in a non-secretory cell type, renin secretion from juxtaglomerular cells as a cAMP-triggered exocytosis from an endocrine cell, insulin release from pancreatic beta-cells as a Ca2+-mediated and cAMP-potentiated exocytic processes in an endocrine cell, and cAMP- or Ca2+ -triggered H+ secretion from gastric parietal cells as an exocytic process in an exocrine cell are discussed. The selected examples of cAMP-regulated exocytic pathways are reviewed with regard to key proteins involved: adenylyl cyclases, phosphodiesterases, PKA, A kinase anchoring proteins (AKAPs) and Epacs.
Leibniz-Institut für Molekulare Pharmakologie, Campus Berlin-Buch, Robert-Rössle-Str. 10, 13125 Berlin, Germany.
Márta
M
Szaszák
Frank
F
Christian
Walter
W
Rosenthal
Enno
E
Klussmann
D000818:Animals; D051399:Aquaporin 2 / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002451:Cell Compartmentation; D000242:Cyclic AMP / Q000378:metabolism*; D005089:Exocytosis; D005744:Gastric Acid / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism; D050417:Insulin-Secreting Cells / Q000378:metabolism; D007606:Juxtaglomerular Apparatus / Q000166:cytology / Q000378:metabolism; D007684:Kidney Tubules / Q000166:cytology / Q000378:metabolism; D008967:Molecular Biology; D010295:Parietal Cells, Gastric / Q000378:metabolism; D012083:Renin / Q000378:metabolism; D015290:Second Messenger Systems
D051399:Aquaporin 2; D007328:Insulin; D000242:Cyclic AMP; D012083:Renin; D002118:Calcium