Cell cycle-dependent coupling of the calcitonin receptor to different G proteins.
Calcitonin is a calcium regulating peptide hormone with binding sites in kidney and bone as well as in the central nervous system. The mechanisms of signal transduction by calcitonin receptors were studied in a pig kidney cell line where the hormone was found to regulate sodium pumps. Calcitonin receptors activated the cyclic adenosine monophosphate (cAMP) or the protein kinase C (PKC) pathways. The two transduction pathways required guanosine triphosphate (GTP)-binding proteins (G proteins) (the choleratoxin sensitive Gs and the pertussis toxin sensitive Gi, respectively) and led to opposite biological responses. Moreover, selective activation of one or the other pathway was cell cycle-dependent. Therefore, calcitonin may induce different biological responses in target cells depending on their positions in the cell cycle. Such a modulation of ligand-induced responses could be of importance in rapidly growing cell populations such as during embryogenesis, growth, and tumor formation.
Chakraborty
M
M
Yale University School of Medicine, Department of Cell Biology, New Haven, CT 06510.
Chatterjee
D
D
Kellokumpu
S
S
Rasmussen
H
H
Baron
R
R
D000262:Adenylyl Cyclases / Q000502:physiology; D000818:Animals; D002116:Calcitonin / Q000502:physiology*; D002453:Cell Cycle; D002460:Cell Line; D019204:GTP-Binding Proteins / Q000502:physiology*; D007668:Kidney; D010042:Ouabain / Q000378:metabolism; D018003:Receptors, Calcitonin; D011956:Receptors, Cell Surface / Q000502:physiology*; D015398:Signal Transduction; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013552:Swine
D018003:Receptors, Calcitonin; D011956:Receptors, Cell Surface; D010042:Ouabain; D002116:Calcitonin; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases; D000254:Sodium-Potassium-Exchanging ATPase