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Phosphorylation of mutationally introduced tyrosine in the activation loop of HER2 confers gain-of-function activity.

Hu Z, Wan X, Hao R, Zhang H, Li L, Li L, Xie Q, Wang P, Gao Y, Chen S, Wei M, Luan Z, Zhang A, Huang N, Chen L - PLoS ONE (2015)

Bottom Line: Y878 represents a phosphorylation site, and phospho-Y878 interacts with R898 residue to stabilize the active conformation of HER2, thereby enhancing its kinase activity.H878Y mutant is transforming and the transformed cells are sensitive to HER2 kinase inhibitors.Thus, our study reveals the following novel mechanism underlying the tumorigenic function of the HER2 H878Y mutation: the introduction of a tyrosine residue into the kinase activation loop via mutagenesis modulates the conformation of the kinase, thereby enhancing its activity.

View Article: PubMed Central - PubMed

Affiliation: College of Life Sciences, Beijing Normal University, Beijing, 100875, China; National Institute of Biological Sciences, Beijing. Beijing, 102206, China.

ABSTRACT
Amplification, overexpression, and somatic mutation of the HER2 gene have been reported to play a critical role in tumorigenesis of various cancers. The HER2 H878Y mutation was recently reported in 11% of hepatocellular carcinoma (HCC) patients. However, its functional impact on the HER2 protein and its role in tumorigenesis has not been determined. Here, we show that HER2 H878Y is a gain-of-function mutation. Y878 represents a phosphorylation site, and phospho-Y878 interacts with R898 residue to stabilize the active conformation of HER2, thereby enhancing its kinase activity. H878Y mutant is transforming and the transformed cells are sensitive to HER2 kinase inhibitors. Thus, our study reveals the following novel mechanism underlying the tumorigenic function of the HER2 H878Y mutation: the introduction of a tyrosine residue into the kinase activation loop via mutagenesis modulates the conformation of the kinase, thereby enhancing its activity.

No MeSH data available.


Related in: MedlinePlus

Y878 is phosphorylated to interact with R898 to enhance HER2 activity.(A) Mass spectrometry detection of Y878 phosphorylation. Red arrow indicates the phosphorylated Y878. (B) Molecular simulation on HER2 H878Y. Picture shows the last snapshot of HER2-pY878 mutant system, where pY878 forms salt bridge interactions with residue R898. (C) The distances of atom pairs pY877-NZK762 (colored in red), pY877-CZR844 (orange) and pY878-CZR898 (blue) in HER2-pY878 simulation. (D) Statistics of soft-agar assay on NIH-3T3 cells transfected with WT, R898A, H878Y, and H878Y/R898A HER2. H878Y/R898A double mutant HER2 transformed cells form similar colonies as WT HER2 on soft-agar assay. **P<0.01.
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pone.0123623.g003: Y878 is phosphorylated to interact with R898 to enhance HER2 activity.(A) Mass spectrometry detection of Y878 phosphorylation. Red arrow indicates the phosphorylated Y878. (B) Molecular simulation on HER2 H878Y. Picture shows the last snapshot of HER2-pY878 mutant system, where pY878 forms salt bridge interactions with residue R898. (C) The distances of atom pairs pY877-NZK762 (colored in red), pY877-CZR844 (orange) and pY878-CZR898 (blue) in HER2-pY878 simulation. (D) Statistics of soft-agar assay on NIH-3T3 cells transfected with WT, R898A, H878Y, and H878Y/R898A HER2. H878Y/R898A double mutant HER2 transformed cells form similar colonies as WT HER2 on soft-agar assay. **P<0.01.

Mentions: Phosphorylation of Y877 confers higher kinase activity of HER2 and correlates with activated states of HER2 [21]. Similar to Y877, the mutationally introduced Y878 locates in the activation loop. We next investigated whether Y878 can also be phosphorylated. Indeed, mass spectrometric data showed that Y878 is phosphorylated (Fig 3A and S1 Fig).


Phosphorylation of mutationally introduced tyrosine in the activation loop of HER2 confers gain-of-function activity.

Hu Z, Wan X, Hao R, Zhang H, Li L, Li L, Xie Q, Wang P, Gao Y, Chen S, Wei M, Luan Z, Zhang A, Huang N, Chen L - PLoS ONE (2015)

Y878 is phosphorylated to interact with R898 to enhance HER2 activity.(A) Mass spectrometry detection of Y878 phosphorylation. Red arrow indicates the phosphorylated Y878. (B) Molecular simulation on HER2 H878Y. Picture shows the last snapshot of HER2-pY878 mutant system, where pY878 forms salt bridge interactions with residue R898. (C) The distances of atom pairs pY877-NZK762 (colored in red), pY877-CZR844 (orange) and pY878-CZR898 (blue) in HER2-pY878 simulation. (D) Statistics of soft-agar assay on NIH-3T3 cells transfected with WT, R898A, H878Y, and H878Y/R898A HER2. H878Y/R898A double mutant HER2 transformed cells form similar colonies as WT HER2 on soft-agar assay. **P<0.01.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390223&req=5

pone.0123623.g003: Y878 is phosphorylated to interact with R898 to enhance HER2 activity.(A) Mass spectrometry detection of Y878 phosphorylation. Red arrow indicates the phosphorylated Y878. (B) Molecular simulation on HER2 H878Y. Picture shows the last snapshot of HER2-pY878 mutant system, where pY878 forms salt bridge interactions with residue R898. (C) The distances of atom pairs pY877-NZK762 (colored in red), pY877-CZR844 (orange) and pY878-CZR898 (blue) in HER2-pY878 simulation. (D) Statistics of soft-agar assay on NIH-3T3 cells transfected with WT, R898A, H878Y, and H878Y/R898A HER2. H878Y/R898A double mutant HER2 transformed cells form similar colonies as WT HER2 on soft-agar assay. **P<0.01.
Mentions: Phosphorylation of Y877 confers higher kinase activity of HER2 and correlates with activated states of HER2 [21]. Similar to Y877, the mutationally introduced Y878 locates in the activation loop. We next investigated whether Y878 can also be phosphorylated. Indeed, mass spectrometric data showed that Y878 is phosphorylated (Fig 3A and S1 Fig).

Bottom Line: Y878 represents a phosphorylation site, and phospho-Y878 interacts with R898 residue to stabilize the active conformation of HER2, thereby enhancing its kinase activity.H878Y mutant is transforming and the transformed cells are sensitive to HER2 kinase inhibitors.Thus, our study reveals the following novel mechanism underlying the tumorigenic function of the HER2 H878Y mutation: the introduction of a tyrosine residue into the kinase activation loop via mutagenesis modulates the conformation of the kinase, thereby enhancing its activity.

View Article: PubMed Central - PubMed

Affiliation: College of Life Sciences, Beijing Normal University, Beijing, 100875, China; National Institute of Biological Sciences, Beijing. Beijing, 102206, China.

ABSTRACT
Amplification, overexpression, and somatic mutation of the HER2 gene have been reported to play a critical role in tumorigenesis of various cancers. The HER2 H878Y mutation was recently reported in 11% of hepatocellular carcinoma (HCC) patients. However, its functional impact on the HER2 protein and its role in tumorigenesis has not been determined. Here, we show that HER2 H878Y is a gain-of-function mutation. Y878 represents a phosphorylation site, and phospho-Y878 interacts with R898 residue to stabilize the active conformation of HER2, thereby enhancing its kinase activity. H878Y mutant is transforming and the transformed cells are sensitive to HER2 kinase inhibitors. Thus, our study reveals the following novel mechanism underlying the tumorigenic function of the HER2 H878Y mutation: the introduction of a tyrosine residue into the kinase activation loop via mutagenesis modulates the conformation of the kinase, thereby enhancing its activity.

No MeSH data available.


Related in: MedlinePlus