RESUMEN
The interrelationships between proteasomes and viral gene products are very complex. 20S proteasomes associate with a number of viral mRNAs which are cleaved by proteasome's associated endonuclease activity. In addition proteasome's endopeptidase activities are involved in the presentation of viral antigens. Viral proteins of different origin associate with the 20S and 26S complexes and interfere with their enzymatic activities. A major part of this review deals with the interactions between 20S proteasomes and the gene products of the human immunodeficiency virus (HIV) which has been studied in detail by our group.
Asunto(s)
Cisteína Endopeptidasas/metabolismo , Complejos Multienzimáticos/metabolismo , ARN Viral/metabolismo , Proteínas Virales/metabolismo , Adenosina Trifosfatasas/metabolismo , VIH/metabolismo , Duplicado del Terminal Largo de VIH , Humanos , Complejo de la Endopetidasa Proteasomal , ARN Mensajero/metabolismo , Aminoacil-ARN de Transferencia/metabolismoRESUMEN
The 20S proteasome (prosome) is a highly organized multiprotein complex with approximate molecular weight of about 700 kDa. Whilst the role of the proteasome in the processing and turnover of cellular proteins is becoming clearer, its relationship with RNA remains still obscure. Here we focus on the nature and function of proteasome associated endonuclease activity. Thus the involvement of a proteasome alpha-type subunit in RNA-degradation, the catalytic requirements, the interaction of proteasomes with their RNA-substrate and the identification of a well defined cleavage site in the 3'UTR of short-lived cellular mRNAs will be described in detail. All data indicate that proteasomes associated endonuclease activity could be involved in post-transcriptional gene control at the level of translation.
Asunto(s)
Cisteína Endopeptidasas/metabolismo , Endorribonucleasas/metabolismo , Complejos Multienzimáticos/metabolismo , Animales , Secuencia de Bases , Humanos , Datos de Secuencia Molecular , Complejo de la Endopetidasa Proteasomal , ARN Mensajero/metabolismo , ARN Viral/metabolismoRESUMEN
The 20S proteasome (prosome) is a highly organized multi-protein complex with approximate molecular weight of about 700 kDa. Whilst the role of the proteasome in the processing and turnover of cellular proteins is becoming clearer, its relationship with RNA remains obscure. Over the last decade the possibility of association of proteasomes with specific RNAs or mRNPs have been particularly controversial. Proteasomes were reported to inhibit translation of viral mRNAs and to be tightly associated with RNase activity. It is possible that proteasomes are also involved in cellular RNA breakdown and RNA processing like prokaryotic RNase E.
Asunto(s)
Cisteína Endopeptidasas/metabolismo , Complejos Multienzimáticos/metabolismo , ARN/metabolismo , Animales , Humanos , Complejo de la Endopetidasa Proteasomal , ARN Mensajero/metabolismo , ARN Viral/metabolismo , Ribonucleasas/metabolismoRESUMEN
1. Rabbit cDNA probes for H and M lactic dehydrogenase subunits were used to monitor mRNA levels in different muscle types during growth. 2. At the same time, lactic dehydrogenase activity and relative quantities of H and M protein subunits were measured. 3. The main results are that mRNA abundance depends on muscle type and age, and mRNA abundance is not correlated with enzymatic activity.