Abstract
Calmodulin regulates numerous fundamental metabolic pathways by binding to and modulating diverse target proteins. In this study, calmodulin-binding proteins were isolated from normal (Hs578Bst) and malignant (MCF-7) human breast cell lines with calmodulin-Sepharose and analyzed by SDS- polyacrylamide gel electrophoresis. A protein that migrated at approximately 190 kDa bound to calmodulin in the presence of Ca2+ and was the only calmodulin-binding protein detected in the absence of Ca2+. This 190-kDa protein was identified as IQGAP1 by nanoelectrospray mass spectrometry and collision-induced dissociation tandem mass spectrometry. IQGAP1 coimmunoprecipitated with calmodulin from lysates of MCF-7 cells. Moreover, overlay with 125I-calmodulin confirmed that IQGAP1 binds directly to calmodulin. Analysis of the functional effects of the interaction revealed that Ca2+/calmodulin disrupted the binding of purified IQGAP1 to the Ras- related protein Cdc42 in a concentration-dependent manner. These data clearly identify IQGAP1 as the predominant calmodulin-binding protein in Ca2+-free breast cell lysates and reveal that calmodulin modulates the interaction between IQGAP1 and Cdc42.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 15419-15425 |
| Number of pages | 7 |
| Journal | Journal of Biological Chemistry |
| Volume | 272 |
| Issue number | 24 |
| DOIs | |
| State | Published - Jun 13 1997 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Calmodulin modulates the interaction between IQGAP1 and Cdc42 : Identification of IQGAP1 by nanoelectrospray tandem mass spectrometry. / Joyal, John L.; Annan, Roland S.; Ho, Yen Dong; Huddleston, Michael E.; Carr, Steven A.; Hart, Matthew J; Sacks, David B.
In: Journal of Biological Chemistry, Vol. 272, No. 24, 13.06.1997, p. 15419-15425.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Calmodulin modulates the interaction between IQGAP1 and Cdc42
T2 - Identification of IQGAP1 by nanoelectrospray tandem mass spectrometry
AU - Joyal, John L.
AU - Annan, Roland S.
AU - Ho, Yen Dong
AU - Huddleston, Michael E.
AU - Carr, Steven A.
AU - Hart, Matthew J
AU - Sacks, David B.
PY - 1997/6/13
Y1 - 1997/6/13
N2 - Calmodulin regulates numerous fundamental metabolic pathways by binding to and modulating diverse target proteins. In this study, calmodulin-binding proteins were isolated from normal (Hs578Bst) and malignant (MCF-7) human breast cell lines with calmodulin-Sepharose and analyzed by SDS- polyacrylamide gel electrophoresis. A protein that migrated at approximately 190 kDa bound to calmodulin in the presence of Ca2+ and was the only calmodulin-binding protein detected in the absence of Ca2+. This 190-kDa protein was identified as IQGAP1 by nanoelectrospray mass spectrometry and collision-induced dissociation tandem mass spectrometry. IQGAP1 coimmunoprecipitated with calmodulin from lysates of MCF-7 cells. Moreover, overlay with 125I-calmodulin confirmed that IQGAP1 binds directly to calmodulin. Analysis of the functional effects of the interaction revealed that Ca2+/calmodulin disrupted the binding of purified IQGAP1 to the Ras- related protein Cdc42 in a concentration-dependent manner. These data clearly identify IQGAP1 as the predominant calmodulin-binding protein in Ca2+-free breast cell lysates and reveal that calmodulin modulates the interaction between IQGAP1 and Cdc42.
AB - Calmodulin regulates numerous fundamental metabolic pathways by binding to and modulating diverse target proteins. In this study, calmodulin-binding proteins were isolated from normal (Hs578Bst) and malignant (MCF-7) human breast cell lines with calmodulin-Sepharose and analyzed by SDS- polyacrylamide gel electrophoresis. A protein that migrated at approximately 190 kDa bound to calmodulin in the presence of Ca2+ and was the only calmodulin-binding protein detected in the absence of Ca2+. This 190-kDa protein was identified as IQGAP1 by nanoelectrospray mass spectrometry and collision-induced dissociation tandem mass spectrometry. IQGAP1 coimmunoprecipitated with calmodulin from lysates of MCF-7 cells. Moreover, overlay with 125I-calmodulin confirmed that IQGAP1 binds directly to calmodulin. Analysis of the functional effects of the interaction revealed that Ca2+/calmodulin disrupted the binding of purified IQGAP1 to the Ras- related protein Cdc42 in a concentration-dependent manner. These data clearly identify IQGAP1 as the predominant calmodulin-binding protein in Ca2+-free breast cell lysates and reveal that calmodulin modulates the interaction between IQGAP1 and Cdc42.
UR - http://www.scopus.com/inward/record.url?scp=0030943857&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030943857&partnerID=8YFLogxK
U2 - 10.1074/jbc.272.24.15419
DO - 10.1074/jbc.272.24.15419
M3 - Article
C2 - 9182573
AN - SCOPUS:0030943857
VL - 272
SP - 15419
EP - 15425
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 24
ER -