title: MAP kinase activation in avian cardiovascular development.
abstract: Signaling pathways mediated by receptor tyrosine kinases (RTK) and mitogen-activated protein kinase (MAPK) activation have multiple functions in the developing cardiovascular system. The localization of diphosphorylated extracellular signal regulated kinase (dp-ERK) was monitored as an indicator of MAPK activation in the forming heart and vasculature of avian embryos. Sustained dp-ERK expression was observed in vascular endothelial cells of embryonic and extraembryonic origins. Although dp-ERK was not detected during early cardiac lineage induction, MAPK activation was observed in the epicardial, endocardial, and myocardial compartments during heart chamber formation. Endocardial expression of dp-ERK in the valve primordia and heart chambers may reflect differential cell growth associated with RTK signaling in the heart. dp-ERK localization in the epicardium, subepicardial fibroblasts, myocardial fibroblasts, and coronary vessels is consistent with MAPK activation in epicardial-derived cell lineages. The complex temporal-spatial regulation of dp-ERK in the heart supports diverse regulatory functions for RTK signaling in different cell populations, including the endocardium, myocardium, and epicardial-derived cells during cardiac organogenesis.
authors.affiliation: Division of Molecular Cardiovascular Biology, Cincinnati Children's Medical Center ML7020, Cincinnati, Ohio 45229, USA.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Liberatore
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Yutzey
mesh_terms: D000818:Animals; D002319:Cardiovascular System / Q000196:embryology*; D019070:Cell Lineage; D002645:Chickens; D003094:Collagen / Q000378:metabolism; D004699:Endocardium / Q000201:enzymology / Q000378:metabolism; D004789:Enzyme Activation; D005775:Gastrula / Q000378:metabolism; D020935:MAP Kinase Signaling System; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism; D010496:Pericardium / Q000196:embryology / Q000201:enzymology / Q000378:metabolism; D010766:Phosphorylation; D011784:Quail; D015398:Signal Transduction; D013997:Time Factors
chemical_list: D003094:Collagen