Degradation of c-Fos protein expressed by N-methyl-D-aspartic acid in nuclear fractions of murine hippocampus.
In both nuclear and cytosolic fractions of murine hippocampus, constitutive expression was seen with Fra-2 protein, but not with other Fos family members tested including c-Fos, Fos-B and Fra-1 proteins. Fos-B protein was only detected in nuclear fractions. The systemic administration of N-methyl-D-aspartic acid (NMDA) induced marked and transient expression of c-Fos protein, but not other family members, in both hippocampal fractions 2 h later. In vitro incubation at 30 degrees C led to more rapid degradation of inducible c-Fos protein than constitutive Fra-2 protein in nuclear fractions obtained 2 h after the administration of NMDA, without significantly affecting that of both member proteins in cytosolic fractions. The addition of phosphatase inhibitors significantly delayed the initial degradation rate of inducible c-Fos protein, with concomitant facilitation of that of constitutive Fra-2 protein, in nuclear fractions. The addition of protease inhibitors also delayed the initial degradation of constitutive Fra-2 protein, without markedly altering that of inducible c-Fos protein, in nuclear fractions. Immunoprecipitation analysis revealed that NMDA induced phosphorylation of c-Fos protein on tyrosine residues in nuclear fractions to a lesser extent than that on serine residues 2 h after administration. These results suggest that NMDA signals may be propagated to the nucleus to induce both expression and degradation of c-Fos protein through a molecular mechanism associated with phosphorylation on serine and/or tyrosine residues in murine hippocampus.
Manabe
T
T
Department of Pharmacology, Setsunan University, Hirakata, Osaka 573-0101, Japan.
Kuramoto
N
N
Nakamichi
N
N
Aramachi
K
K
Baba
K
K
Hirai
T
T
Yoneyama
M
M
Yoneda
Y
Y
D000818:Animals; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000378:metabolism; D018690:Excitatory Amino Acid Agonists / Q000378:metabolism / Q000494:pharmacology*; D051921:Fos-Related Antigen-2; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D007150:Immunohistochemistry; D051379:Mice; D016202:N-Methylaspartate / Q000378:metabolism / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D016760:Proto-Oncogene Proteins c-fos / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D013997:Time Factors; D014157:Transcription Factors / Q000187:drug effects / Q000378:metabolism; D000099169:Fos-Related Antigen 1
D004268:DNA-Binding Proteins; D018690:Excitatory Amino Acid Agonists; D051921:Fos-Related Antigen-2; D016202:N-Methylaspartate; D016760:Proto-Oncogene Proteins c-fos; D014157:Transcription Factors; D000099169:Fos-Related Antigen 1; C497873:Fosl2 protein, mouse