RESUMO
To investigate the function of the alpha calcium-calmodulin-dependent kinase II (alphaCaMKII) inhibitory autophosphorylation at threonines 305 and/or 306, we generated knockin mice that express alphaCaMKII that cannot undergo inhibitory phosphorylation. In addition, we generated mice that express the inhibited form of alphaCaMKII, which resembles the persistently phosphorylated kinase at these sites. Our data demonstrate that blocking inhibitory phosphorylation increases CaMKII in the postsynaptic density (PSD), lowers the threshold for hippocampal long-term potentiation (LTP), and results in hippocampal-dependent learning that seems more rigid and less fine-tuned. Mimicking inhibitory phosphorylation dramatically decreased the association of CaMKII with the PSD and blocked both LTP and learning. These data demonstrate that inhibitory phosphorylation has a critical role in plasticity and learning.
Assuntos
Proteínas Quinases Dependentes de Cálcio-Calmodulina/deficiência , Hipocampo/enzimologia , Aprendizagem/fisiologia , Potenciação de Longa Duração/genética , Terminações Pré-Sinápticas/enzimologia , Membranas Sinápticas/enzimologia , Transmissão Sináptica/genética , Animais , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina , Proteínas Quinases Dependentes de Cálcio-Calmodulina/genética , Estimulação Elétrica , Antagonistas de Aminoácidos Excitatórios/farmacologia , Feminino , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica/genética , Hipocampo/crescimento & desenvolvimento , Aprendizagem/efeitos dos fármacos , Potenciação de Longa Duração/efeitos dos fármacos , Depressão Sináptica de Longo Prazo/efeitos dos fármacos , Depressão Sináptica de Longo Prazo/genética , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/genética , Camundongos , Camundongos Transgênicos , Técnicas de Cultura de Órgãos , Fosforilação , Terminações Pré-Sinápticas/efeitos dos fármacos , Membranas Sinápticas/efeitos dos fármacos , Transmissão Sináptica/efeitos dos fármacosRESUMO
Congenital absence of pain perception is a rare phenotype. Here we report two unrelated adult individuals who have a previously unreported neuropathy consisting of congenital absence of pain with hyperhidrosis (CAPH). Both subjects had normal intelligence and productive lives despite failure to experience pain due to broken bones, severe cold or burns. Functional assessments revealed that both are generally hypesthetic with thresholds greater than two standard deviations above normal for a several of modalities in addition to noxious stimuli. Sweating was 3 to 8-fold greater than normal. Sural nerve biopsy showed that all types of myelinated and unmyelinated fibers were severely reduced. Extensive multi-antibody immunofluorescence analyses were conducted on several skin biopsies from the hands and back of one CAPH subject and two normal subjects. The CAPH subject had all normal types of immunochemically and morphologically distinct sensory and autonomic innervation to the vasculature and sweat glands, including a previously unknown cholinergic arterial innervation. Virtually all other types of normal cutaneous C, Adelta and Abeta-fiber endings were absent. This subject had no mutations in the genes SCN9A, SCN10A, SCN11A, NGFB, TRKA, NRTN and GFRA2. Our findings suggest three hypotheses: (1) that development or maintenance of sensory innervation to cutaneous vasculature and sweat glands may be under separate genetic control from that of all other cutaneous sensory innervation, (2) the latter innervation is preferentially vulnerable to some environmental factor, and (3) vascular and sweat gland afferents may contribute to conscious cutaneous perception.