Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1981-5-28
pubmed:abstractText
We have uniformly labeled calmodulin with tetramethyl rhodamine isothiocyanate (CaM-RITC) and used the derivative as a molecular probe in order to identify available, unoccupied calmodulin-binding sites. In mildly fixed (3% formalin) cultured 3T3 cells, the biologically active CaM-RITC bound predominantly to mitochondria. Binding was markedly reduced in the presence of 1 mM EGTA. Stelazine, a phenothiozine which binds to calmodulin, prevented the interaction of CaM-RITC with mitochondrial sites. A 10 fold excess of unlabeled CaM competitively inhibited binding. Fluorescently labeled troponin C and parvalbumin did not bind to mitochondria on any other cellular organelle. Rhodamine (TMRITC) alone did not bind to 3T3 mitochondria. Similar results were obtained using 125I-calmodulin binding to isolated rat liver mitochondria. When solubilized mitochondrial proteins were subjected to calmodulin-Sepharose affinity chromatography and eluted with 1 mM EGTA, there were two major polypeptides 120,000 and 67,000 daltons and at least three minor species (100,000, 60,000 and 40,000 daltons). The interaction required an active Ca2+-CaM complex and is specific for CaM. Double fluorescent staining with CaM-RITC and fluorescein-labeled antibodies to tubulin and DNAase I revealed a mitochondrial distribution pattern similar to that of microtubule arrays but unrelated to actin cabling. There was no evidence that CaM-RITC directly interacted with either microtubules or microfilaments.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0092-8674
pubmed:author
pubmed:issnType
Print
pubmed:volume
23
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
533-42
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1981
pubmed:articleTitle
The identification of calmodulin-binding sites on mitochondria in cultured 3T3 cells.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't