Rho/ROCK Pathway Contributes to the Activation of Extracellular Signal-regulated Kinase/GATA-4 during Myocardial Cell Hypertrophy

Abstract

Cardiac myocytes within the adult heart are terminally differentiated and do not undergo cell division. In response to stimuli that affect the mechanical load on the heart or in response to various neurohumoral factors, the heart adapts through the activation of a hypertrophic response in individual cardiac muscle cells. This response is characterized by an increase in myocyte size, accumulation of contractile proteins within individual cardiac cells, and activation of embryonic gene marker expression (for reviews, see Refs. 1-3). For example, genes such as ␤-myosin heavy chain (MHC) 1 and atrial natriuretic factor become highly expressed within ventricular myocytes (4 -6). Studies focused on elucidating the mechanisms of transcriptional regulation of these genes have identified a group of DNA-binding factors that might mediate the nuclear response to hypertrophic stimuli. These factors include the GATA family of zinc finger transcription factors, which mediate transcriptional activation of the genes for ␤-MHC and angiotensin II type 1a receptor during pressure overload-induced hypertrophy in vivo (7-9). GATA factors are also required for the transcriptional activation of the endothelin-1

Rho‐associated kinases play an essential role in cardiac morphogenesis and cardiomyocyte proliferation

“…These serine/ threonine kinases phosphorylate a large number of substrates, including cytoskeletal proteins, myosin light chain, LIM kinase, and myosin phosphatase (Nakagawa et al, 1996;Amano et al, 2000). ROCK kinases also influence activity of transcription factors (Kuwahara et al, 1999;Yanazume et al, 2002). ROCK kinases are involved in a wide spectrum of cell activities, including cytoskeleton organization, focal adhesion, cell division, cell migration, apoptosis, smooth muscle contraction, and cardiomyocyte hypertrophy (Kuwahara et al, 1999;Amano et al, 2000;Bishop and Hall, 2000;Sah et al, 2000;Aznar and Lacal, 2001;Pruitt and Der, 2001;Yanazume et al, 2002).…”

Identification and validation of an ERBB2 gene expression signature in breast cancers

“…Investigation of the functional relationship between ERBB2, GATA4 and MAP2K6 may enhance current understanding of cardiotoxicities associated with ERBB2 antagonists, and contribute to design ways to circumvent this side effect. Activation of GATA4 is thought to occur through RHO GTPases (Yanazume et al, 2002), which are also central to the functions of integrins and cadherins (for a review, see Arthur et al, 2002). Figure 5 Localization of genes from chromosome 17q12-24 region represented on the DNA microarray.…”

Acetylation of GATA-4 Is Involved in the Differentiation of Embryonic Stem Cells into Cardiac Myocytes

“…After a 24-h incubation, cells were subjected to immunocytochemistry for ␤-myosin heavy chain (MHC) as previously described (11). Briefly, after fixation the cells were incubated with anti-cardiac ␤-MHC monoclonal antibody (Novocastra Laboratories) at a dilution of 1:50, followed by incubation with anti-mouse horseradish peroxidase-conjugated secondary antibody (Jackson ImmunoResearch) at a dilution of 1:200.…”

“…The detection of acetylated GATA-4 was also analyzed by pulse labeling as previously described (8). Briefly, EBs were resuspended in 2.5 ml of medium containing 0.05 mCi of [1][2][3][4][5][6][7][8][9][10][11][12][13][14] C]acetic acid sodium salt/ml (200 Ci/ml; Amersham Biosciences) and incubated for 3 h. Ethanol, the solvent of [1-14 C]acetic acid sodium salt, was removed by evaporation to minimize the cytotoxic effect of the ethanol in the culture medium. Nuclear extracts from these cells were immunoprecipitated using goat anti-GATA-4 antibody (Santa Cruz Biotechnology) or normal goat IgG in low stringency buffer for 16 h at 4°C and incubated with protein G beads for 1 h at 4°C.…”