scholarly journals Insulin-Like Growth Factor Type 1 Receptor and Insulin Receptor Isoform Expression and Signaling in Mammary Epithelial Cells

Endocrinology ◽  
2009 ◽  
Vol 150 (8) ◽  
pp. 3611-3619 ◽  
Author(s):  
Anne M. Rowzee ◽  
Dale L. Ludwig ◽  
Teresa L. Wood

The insulin receptor (IR) isoforms and the IGF type 1 receptor (IGF-1R) share a high degree of structural homology but differ in ligand binding kinetics and functions. We developed a highly specific quantitative PCR assay to quantify and compare IR-A, IR-B, and IGF-1R expression within an RNA population. We determined receptor expression in primary murine mammary epithelial cells (MECs) during postnatal development. Both IR isoform mRNAs were 3- to 16-fold higher than IGF-1R expression at all developmental times. IR protein was also 3- to 10-fold higher than IGF-1R protein; however, significantly less IGF-1R was found in hybrid receptors at early (49%) vs. late (79%) pregnancy, indicating that the amount of hybrid receptor is developmentally regulated. Despite high IR expression, IGF ligands were more effective than insulin in stimulating the insulin receptor substrate-1/phosphatidylinositol 3-kinase/Akt pathway in acutely isolated MECs from virgin glands. Although approximately 40% of IR transcripts were the IGF-II-sensitive IR-A isoform, IGF-II failed to stimulate IR phosphorylation, and an IGF-1R-specific blocking antibody completely abrogated IGF-II-mediated Akt phosphorylation in the virgin MECs. Taken together, these data suggest that the IGF-1R is more active in signaling than the IR and is the predominant mediator of IGF actions in virgin MECs.

2011 ◽  
Vol 32 (10) ◽  
pp. 1441-1449 ◽  
Author(s):  
Nune Markosyan ◽  
Edward P. Chen ◽  
Victoire N. Ndong ◽  
Yubing Yao ◽  
Christopher J. Sterner ◽  
...  

2015 ◽  
Author(s):  
Yekaterina Poloz ◽  
Mariam Z. El Sheikh ◽  
Julia Petschnigg ◽  
Bella Groisman ◽  
Max Kotlyar ◽  
...  

1999 ◽  
Vol 78 (7) ◽  
pp. 511-523 ◽  
Author(s):  
Kathleen M. Darcy ◽  
Ann L. Wohlhueter ◽  
Danilo Zangani ◽  
Mary M. Vaughan ◽  
Joy A. Russell ◽  
...  

2006 ◽  
Vol 66 (21) ◽  
pp. 10460-10465 ◽  
Author(s):  
Vladislav S. Golubkov ◽  
Alexey V. Chekanov ◽  
Alexey Y. Savinov ◽  
Dmitri V. Rozanov ◽  
Natalya V. Golubkova ◽  
...  

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