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Target Concepts:
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Query: UMLS:C0018799 (
heart disease
)
34,133
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Cardiac neural crest cells are multipotent migratory cells that contribute to the formation of the cardiac outflow tract and pharyngeal arch arteries. Neural crest-related developmental defects account for a large proportion of congenital heart disorders. Recently, the genetic bases for some of these disorders have been elucidated, and signaling pathways required for induction, migration and differentiation of cardiac neural crest have emerged. Bone morphogenetic proteins comprise a family of secreted ligands implicated in numerous aspects of organogenesis, including heart and neural crest development. However, it has remained generally unclear whether BMP ligands act directly on neural crest or cardiac myocytes during cardiac morphogenesis, or function indirectly by activating other cell types. Studies on BMP receptor signaling during organogenesis have been hampered by the fact that receptor knockouts often lead to early embryonic lethality. We have used a Cre/loxP system for neural crest-specific deletion of the type I receptor,
ALK2
, in mouse embryos. Mutant mice display cardiovascular defects, including persistent truncus arteriosus, and abnormal maturation of the aortic arch reminiscent of common forms of human congenital
heart disease
. Migration of mutant neural crest cells to the outflow tract is impaired, and differentiation to smooth muscle around aortic arch arteries is deficient. Moreover, in Alk2 mutants, the distal outflow tract fails to express Msx1, one of the major effectors of BMP signaling. Thus, the type I BMP receptor
ALK2
plays an essential cell-autonomous role in the development of the cardiac outflow tract and aortic arch derivatives.
...
PMID:Cardiac outflow tract defects in mice lacking ALK2 in neural crest cells. 1522 63
Fibrodysplasia ossificans progressiva (FOP) is a genetic disorder characterized by progressive heterotopic ossification in soft tissues, such as the skeletal muscles. FOP has been shown to be caused by gain-of-function mutations in activin receptor-like kinase (ALK)-2, which is a type I receptor for bone morphogenetic proteins (BMPs). In the present study, we examined the molecular mechanisms that underlie the activation of intracellular signaling by mutant
ALK2
. Mutant
ALK2
from FOP patients enhanced the activation of intracellular signaling by type II BMP receptors, such as BMPR-II and activin receptor, type II B, whereas that from
heart disease
patients did not. This enhancement was dependent on the kinase activity of the type II receptors. Substitution mutations at all nine serine and threonine residues in the
ALK2
glycine- and serine-rich domain simultaneously inhibited this enhancement by the type II receptors. Of the nine serine and threonine residues in
ALK2
, T203 was found to be critical for the enhancement by type II receptors. The T203 residue was conserved in all of the BMP type I receptors, and these residues were essential for intracellular signal transduction in response to ligand stimulation. The phosphorylation levels of the mutant
ALK2
related to FOP were higher than those of wild-type
ALK2
and were further increased by the presence of type II receptors. The phosphorylation levels of
ALK2
were greatly reduced in mutants carrying a mutation at T203, even in the presence of type II receptors. These findings suggest that the mutant
ALK2
related to FOP is enhanced by BMP type II receptors via the T203-regulated phosphorylation of
ALK2
.
...
PMID:Mutant activin-like kinase 2 in fibrodysplasia ossificans progressiva are activated via T203 by BMP type II receptors. 2535 96