PROTEASOME (PROSOME) ASSOCIATED ENDONUCLEASE ACTIVITY

The 20S proteasome (prosome) is a highly organized multiprotein comple x 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 endo nuclease activity. Thus the involvement of a proteasome alpha-type sub unit in RNA-degradation, the catalytic requirements, the interaction o f proteasomes with their RNA-substrate and the identification of a wel l defined cleavage site in the 3'UTR of short-lived cellular mRNAs wil l be described in detail. All data indicate that proteasomes associate d endonuclease activity could be involved in post-transcriptional gene control at the level of translation.