P62 and the sequestosome, a novel mechanism for protein metabolism.
In addition to selecting proteins for degradation by the 26S proteasome, ubiqitination appears to serve other regulatory functions, including for endosomal/lysosomal targeting, protein translocation, and enzyme modification. Currently, little is known how multiubiquitin chains are recognized by these cellular mechanisms. Within the 26S proteasome, one subunit (Mcb1/S5a) has been identified that has affinity for multiubiquitin chains and may function as a ubiquitin receptor. We recently found that a non-proteasomal protein p62 also preferentially binds multiubiquitin chains and forms a novel cytoplasmic structure "sequestosome" which serves as a storage place for ubiquitinated proteins. In the present manuscript, the role and regulation of p62 in relation to the sequestosomal function will be reviewed.
Shin
J
J
Division of Tumor Virology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D003546:Cysteine Endopeptidases / Q000378:metabolism; D006801:Humans; D009097:Multienzyme Complexes / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014452:Ubiquitins / Q000378:metabolism*
D009097:Multienzyme Complexes; D011506:Proteins; D016271:Proto-Oncogene Proteins c-myc; D014452:Ubiquitins; D011494:Protein Kinases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D000251:Adenosine Triphosphatases