Degree Of Kinase Activation Research Articles

Mapk/Erk activation in an animal model of social deficits shows a possible link to autism.

BackgroundThere is converging preclinical and clinical evidence to suggest that the extracellular signal-regulated kinase (ERK) signaling pathway may be dysregulated in autism spectrum disorders.MethodWe evaluated Mapk/Erk1/2, cellular proliferation and apoptosis in BTBR mice, as a preclinical model of Autism. We had previously generated 410 F2 mice from the cross of BTBR with B6. At that time, six different social behaviors in all F2 mice were evaluated and scored. In this study, eight mice at each extreme of the social behavioral spectrum were selected and the expression and activity levels of Mapk/Erk in the prefrontal cortex and cerebellum of these mice were compared. Finally, we compared the Mapk/Erk signaling pathway in brain and lymphocytes of the same mice, testing for correlation in the degree of kinase activation across these separate tissues.ResultsLevels of phosphorylated Erk (p-Erk) were significantly increased in the brains of BTBR versus control mice. We also observed a significant association between juvenile social behavior and phosphorylated mitogen-activated protein kinase kinase (p-Mek) and p-Erk levels in the prefrontal cortex but not in the cerebellum. In contrast, we did not find a significant association between social behavior and total protein levels of either Mek or Erk. We also tested whether steady-state levels of Erk activation in the cerebral cortex in individual animals correlated with levels of Erk activation in lymphocytes, finding a significant relationship for this signaling pathway.ConclusionThese observations suggest that dysregulation of the ERK signaling pathway may be an important mediator of social behavior, and that measuring activation of this pathway in peripheral lymphocytes may serve as a surrogate marker for central nervous system (CNS) ERK activity, and possibly autistic behavior.Electronic supplementary materialThe online version of this article (doi:10.1186/2040-2392-5-57) contains supplementary material, which is available to authorized users.

Activation of protein kinase isoenzymes under near physiological conditions: Evidence that both types (A and B) of cAMP binding sites are involved in the activation of protein kinase by cAMP and 8-N 3-cAMP

cAMP-dependent protein kinase I and II (cAKI and cAKII) were incubated under near physiological conditions in the presence of various concentrations of 8-N 3-c[ 3H]AMP or c[ 3H]AMP. Both types (A and B) of cyclic nucleotide binding sites of cAKI or cAKII were occupied to a similar extent and the degree of their occupation correlated with the degree of kinase activation. cAKI cAKII bound cAMP in an apparent positively cooperative manner in the presence of Mg 2+, ATP. 8-N 3-c[ 3H]AMP dissociated several orders of magnitude faster from site A than site B of the regulatory moeity of cAKII, and was photo-incorporated only when bound to site B.

Effect of PGEi and TSH on cAMP-Dependent Protein Kinase Activity in the Thyroid

PGE1, like TSH, can increase cAMP-dependent protein kinase activity in calf thyroid slices. The intracellular levels of cAMP produced by either of these agents alone appeared to correlate well with the degree of kinase activation. PG synthesis did not appear to be necessary for TSH action in this system, since indomethacin, and inhibitor of prostaglandin synthesis, did not alter either cAMP levels or kinase activity in slices incubated with TSH. Both the cAMP level and kinase activity rose when a submaximally effective dose of TSH was added to a maximal dose of PGE1. However, neither the cAMP levels nor the kinase activity produced by a maximal dose of TSH was affected by the addition of PGE1.