Gab family proteins are essential for postnatal maintenance of cardiac function via neuregulin-1/ErbB signaling.
Grb2-associated binder (Gab) family of scaffolding adaptor proteins coordinate signaling cascades downstream of growth factor and cytokine receptors. In the heart, among EGF family members, neuregulin-1beta (NRG-1beta, a paracrine factor produced from endothelium) induced remarkable tyrosine phosphorylation of Gab1 and Gab2 via erythroblastic leukemia viral oncogene (ErbB) receptors. We examined the role of Gab family proteins in NRG-1beta/ErbB-mediated signal in the heart by creating cardiomyocyte-specific Gab1/Gab2 double knockout mice (DKO mice). Although DKO mice were viable, they exhibited marked ventricular dilatation and reduced contractility with aging. DKO mice showed high mortality after birth because of heart failure. In addition, we noticed remarkable endocardial fibroelastosis and increase of abnormally dilated vessels in the ventricles of DKO mice. NRG-1beta induced activation of both ERK and AKT in the hearts of control mice but not in those of DKO mice. Using DNA microarray analysis, we found that stimulation with NRG-1beta upregulated expression of an endothelium-stabilizing factor, angiopoietin 1, in the hearts of control mice but not in those of DKO mice, which accounted for the pathological abnormalities in the DKO hearts. Taken together, our observations indicated that in the NRG-1beta/ErbB signaling, Gab1 and Gab2 of the myocardium are essential for both maintenance of myocardial function and stabilization of cardiac capillary and endocardial endothelium in the postnatal heart.
Nakaoka
Yoshikazu
Y
Department of Structural Analysis, National Cardiovascular Center Research Institute, Osaka, Japan.
Nishida
Keigo
K
Narimatsu
Masahiro
M
Kamiya
Atsunori
A
Minami
Takashi
T
Sawa
Hirofumi
H
Okawa
Katsuya
K
Fujio
Yasushi
Y
Koyama
Tatsuya
T
Maeda
Makiko
M
Sone
Manami
M
Yamasaki
Satoru
S
Arai
Yuji
Y
Koh
Gou Young
GY
Kodama
Tatsuhiko
T
Hirota
Hisao
H
Otsu
Kinya
K
Hirano
Toshio
T
Mochizuki
Naoki
N
D048868:Adaptor Proteins, Signal Transducing; D042683:Angiopoietin-1 / Q000235:genetics / Q000378:metabolism; D000818:Animals; D018376:Cardiovascular Abnormalities / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002478:Cells, Cultured; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D020869:Gene Expression Profiling; D006321:Heart / Q000502:physiology*; D020935:MAP Kinase Signaling System; D051379:Mice; D018345:Mice, Knockout; D009206:Myocardium / Q000378:metabolism*; D020890:Neuregulin-1 / Q000378:metabolism*; D018739:Oncogene Proteins v-erbB / Q000378:metabolism*; D010750:Phosphoproteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D015854:Up-Regulation
D048868:Adaptor Proteins, Signal Transducing; D042683:Angiopoietin-1; C490897:Gab1 protein, mouse; C490894:Gab2 protein, mouse; D020890:Neuregulin-1; D018739:Oncogene Proteins v-erbB; D010750:Phosphoproteins; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases