cAMP signalling mechanisms with aging in the Ceratitis capitata brain.
Aging has been associated with alterations in protein phosphorylation. This study was undertaken to examine eventual changes in cAMP-dependent protein kinase (PKA) activity and enzyme regulatory subunit levels from the dipterous Ceratitis capitata brain with postmaturational aging and senescence. PKA activity was determined in cytosolic and membrane fractions of the C. capitata brain during the adult stage of the insect lifespan. PKA activity markedly increased at the first stages of the life of the fly both in cytosol and in membranes. A lower peak of PKA activity was evident both in particulate and cytosolic fractions in the terminal phase of the life of the fly. Thus, PKA activity was significantly higher in the brain of mature flies when compared to the brain of aged flies. It is possible that increases in cAMP-dependent protein phosphorylation levels characterize the terminal aging process in the insect nervous tissue. On the other hand, levels of regulatory (R) subunit were also measured in membranes and cytosol by immunoblotting. Cytosolic regulatory subunit levels were more elevated near the terminal phase of life, whereas in membranes, regulatory subunit levels decrease in senescence in parallel with particulate PKA activity. The increased R subunit level in cytosol may reflect a cellular response mechanisms to down-regulate the kinase system in aged flies.
Laviada
I D
ID
Departamento de Bioquímica y Biología Molecular I, Fac. Químicas, Universidad Complutense, Madrid, Spain.
Galve-Roperh
I
I
Malpartida
J M
JM
Haro
A
A
D000375:Aging / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D001921:Brain / Q000378:metabolism* / Q000502:physiology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004175:Diptera / Q000378:metabolism / Q000502:physiology*; D010766:Phosphorylation; D015398:Signal Transduction / Q000502:physiology
D017868:Cyclic AMP-Dependent Protein Kinases