Linked Life Data

21478150

Source:http://linkedlifedata.com/resource/pubmed/id/21478150

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
2011-5-30
pubmed:abstractText
The molecular chaperone prefoldin (PFD) is a complex comprised of six different subunits, PFD1-PFD6, and delivers newly synthesized unfolded proteins to cytosolic chaperonin TRiC/CCT to facilitate the folding of proteins. PFD subunits also have functions different from the function of the PFD complex. We previously identified MM-1?/PFD5 as a novel c-Myc-binding protein and found that MM-1? suppresses transformation activity of c-Myc. However, it remains unclear how cells regulate protein levels of individual subunits and what mechanisms alter the ratio of their activities between subunits and their complex. In this study, we found that knockdown of one subunit decreased protein levels of other subunits and that transfection of five subunits other than MM-1? into cells increased the level of endogenous MM-1?. We also found that treatment of cells with MG132, a proteasome inhibitor, increased the level of transfected/overexpressed MM-1? but not that of endogenous MM-1?, indicating that overexpressed MM-1?, but not endogenous MM-1?, was degraded by the ubiquitin proteasome system (UPS). Experiments using other PFD subunits showed that the UPS degraded a monomer of PFD subunits, though extents of degradation varied among subunits. Furthermore, the level of one subunit was increased after co-transfection with the respective subunit, indicating that there are specific combinations between subunits to be stabilized. These results suggest mutual regulation of protein levels among PFD subunits and show how individual subunits form the PFD complex without degradation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Carrier Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Cysteine Proteinase Inhibitors, http://linkedlifedata.com/resource/pubmed/chemical/Leupeptins, http://linkedlifedata.com/resource/pubmed/chemical/MM-1 protein, mouse, http://linkedlifedata.com/resource/pubmed/chemical/MYC protein, human, http://linkedlifedata.com/resource/pubmed/chemical/Multiprotein Complexes, http://linkedlifedata.com/resource/pubmed/chemical/Myc protein, mouse, http://linkedlifedata.com/resource/pubmed/chemical/PFDN5 protein, human, http://linkedlifedata.com/resource/pubmed/chemical/Proteasome Endopeptidase Complex, http://linkedlifedata.com/resource/pubmed/chemical/Proto-Oncogene Proteins c-myc, http://linkedlifedata.com/resource/pubmed/chemical/Repressor Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Ubiquitin, http://linkedlifedata.com/resource/pubmed/chemical/benzyloxycarbonylleucyl-leucyl-leuci...
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1083-351X
pubmed:author
pubmed:issnType
Electronic
pubmed:day
3
pubmed:volume
286
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
19191-203
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Prefoldin subunits are protected from ubiquitin-proteasome system-mediated degradation by forming complex with other constituent subunits.
pubmed:affiliation
Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't