Preferred Label : NFAT Pathway;
NCIt related terms : NFAT and Hypertrophy of the heart (Transcription in the broken heart);
Alternative definition : BIOCARTA: Hypertrophy associated with both hypertension and obstruction to ventricular
outflow leads to pathologic cardiac growth and it is associated with increase morbidity
and mortality. Symptomatic ventricular disease takes a growing toll on the health
of nations. As other cardiovascular diseases such as stroke and myocardial infarction
are in decline as causes of mortality, the heart failure problem becomes increasingly
urgent. Congenital heart defects occur in 1% of live births and fetal heart malformations
are implicated in many pregnancies that end in still-birth or spontaneous abortion.
The current paradigm suggests that the heart adapts to excess of hemodynamic loading
by compensatory hypertrophy, which under condition of persistent stress, over time
evolves into dysfunction and myocardial failure. There is considerable evidence that
direct effects of increased mechanical stress are sensed within the ventricular wall
and that signal is critical for the generation of growth responses. Despite compelling
statistics we still do not understand biochemically why heart defects are so prevalent.
A single transcriptional regulator initially associated with the activation of the
T-cells (NFATc4) has been shown to link genetic and environmental causes of one class
of congenital heart disorders, birth defects involving valve and septum formation.
Within the endocardium, specific inductive events appear to activate NF-ATc: it is
localized to the nucleus only in endocardial cells that are adjacent to the interface
with the cardiac jelly and myocardium, which are thought to give the inductive stimulus
to the valve primordia. Treatment with FK506, a specific calcineurin inhibitor, prevents
nuclear localization of NF-ATc4. Activated CaMK stimulates calcineurin, which than
acts through NF-ATc4 in association with GATA4, to induce hypertrophy. A model for
the proposed role of calreticulin in the regulation of cardiac development requires
a myogenic signal from extracellular space to activate the production of IP3 that
results in the release of Ca2 from ER under the regulation of calreticulin (CRT).
Increased intracellular Ca2 binds to calmodulin (CaM) and activates calcineurin (CaN).
CaN dephosphorylates NF-ATc4 that translocates to the nucleus. In the nucleus NF-AT
forms complexes with the GATA-4 and other transcription factors leading to activation
of transcription of genes (e.g., ANF, a-actin, b-myosin, TNFa, ET-1, Adss1) essential
for cardiac development. (This definition may be outdated - see the DesignNote.);
NCIt note : The BIOCARTA Definition (ALT_DEFINITION) for this pathway concept was provided by
BioCarta. This property was not created by, nor is it maintained by the NCI Thesaurus
staff. Additionally, BioCarta is no longer updating its pathway data; thus, the BIOCARTA
Definition might be outdated or inaccurate. Please see the Terms and Conditions for
Use at http://www.biocarta.com/.;
Biocarta ID : h_nfatPathway;
Origin ID : C39162;
UMLS CUI : C1513836;
Semantic type(s)
has_gene_product_element
pathway_has_gene_element