Characterization of cyclic nucleotide phosphodiesterase isoforms associated to isolated cardiac nuclei.
Biochim Biophys Acta
; 1472(3): 431-46, 1999 Nov 16.
Article
em En
| MEDLINE
| ID: mdl-10564757
ABSTRACT
The identity and location of nuclear cyclic nucleotide phosphodiesterases (PDE) has yet to be ascertained. Intact cardiac nuclei and subnuclear fractions from ovine hearts were isolated to determine cAMP-specific PDE activity which was 3-fold greater than that of cGMP PDE, the latter being insensitive to Ca-calmodulin and zaprinast. Specific hydrolytic activities of the cardiac nuclear envelopes (NE) were similar to those measured in the corresponding intact nuclei, thus suggesting that most PDE activity is associated with the nuclear membrane. Moreover, the main hydrolytic activities in cardiac nuclei were attributed to PDE4 (56%) and PDE3 (44%). The pharmacological sensitivity of each isoform in terms of IC(50), K(m) and K(i) values was typical of previously characterized cardiac PDE 3 and 4 isoforms. PDE2 (cGMP-stimulated PDE) represented a minor component (8-9%) of total hydrolytic activity. Solubilization of nuclear envelopes and HPLC separation also yielded rolipram-sensitive PDE activities. Upon 1% Triton X-100 extractions, the presence of PDE3 and PDE4 was revealed in a low speed, nucleopore complex-enriched, P1 pellet. In addition, Western blot analysis demonstrated the presence of PDE4B and PDE4D subtypes in the nuclei as well as enrichment in NE. However, in the same preparations, the presence of PDE4A could not be ascertained. Altogether, these results suggest an intrinsic and predominant association of these nuclear PDEs with the NE and much likely with nucleopore complexes.
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Bases de dados:
MEDLINE
Assunto principal:
3',5'-AMP Cíclico Fosfodiesterases
/
Miocárdio
Tipo de estudo:
Risk_factors_studies
Limite:
Animals
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1999
Tipo de documento:
Article
País de afiliação:
França