Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
35
pubmed:dateCreated
2009-9-3
pubmed:abstractText
Our laboratory has previously described the presence of five tumor-specific low molecular weight isoforms of cyclin E in both tumor cell lines and breast cancer patient biopsies. We have also shown that one of these low forms arises from an alternate start site, whereas the other four appear as two sets of doublets following cleavage through an elastase-like enzyme. However, the origin of both sets of doublets was unknown. Here, we demonstrate that the larger isoform of each doublet is the result of phosphorylation at a key degradation site. Through site-directed mutagenesis of different phosphorylation sites within the cyclin E protein, we discovered that phosphorylation of threonine 395 is responsible for generating the larger isoform of each doublet. Because phosphorylation of threonine 395 has been linked to the proteasome-mediated degradation of full length cyclin E, we examined the stability of T395A phospho-mutants in both non-tumorigenic mammary epithelial cells and tumor cells. The results revealed that the low molecular weight isoforms appear to be stable in both a tumor cell line and a non-tumor forming cell line regardless of the presence of this critical phosphorylation site. The stability of low molecular weight cyclin E may have implications for both tumorigenesis and treatment of tumors expressing them.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1476-5594
pubmed:author
pubmed:issnType
Electronic
pubmed:day
3
pubmed:volume
28
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3167-76
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:19561641-Alanine, pubmed-meshheading:19561641-Amino Acid Sequence, pubmed-meshheading:19561641-Amino Acid Substitution, pubmed-meshheading:19561641-Breast Neoplasms, pubmed-meshheading:19561641-Cell Line, pubmed-meshheading:19561641-Cell Line, Tumor, pubmed-meshheading:19561641-Cyclin E, pubmed-meshheading:19561641-Cyclin-Dependent Kinase 2, pubmed-meshheading:19561641-Cyclin-Dependent Kinase Inhibitor p27, pubmed-meshheading:19561641-Humans, pubmed-meshheading:19561641-Kidney, pubmed-meshheading:19561641-Models, Biological, pubmed-meshheading:19561641-Molecular Sequence Data, pubmed-meshheading:19561641-Molecular Weight, pubmed-meshheading:19561641-Phosphorylation, pubmed-meshheading:19561641-Protamine Kinase, pubmed-meshheading:19561641-Protein Binding, pubmed-meshheading:19561641-Protein Isoforms, pubmed-meshheading:19561641-Protein Processing, Post-Translational, pubmed-meshheading:19561641-Transfection, pubmed-meshheading:19561641-p21-Activated Kinases
pubmed:year
2009
pubmed:articleTitle
Post-translational modification and stability of low molecular weight cyclin E.
pubmed:affiliation
Department of Experimental Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, TX 77030, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural