PI3K reg class IA, PLC-beta3, MEK6(MAP2K6), PKC-delta, PtdIns(3,4,5)P3, IP3 receptor, EDNRA, H(,2)O + 1-(1,2-diacyl-glycerol 3-phospho)-inositol 4,5-bisphosphate = 1,2-diacyl-glycerol + inositol 1,4,5-trisphosphate, G-protein alpha-i family, BNP, Ca('2) cytosol, cAMP, c-Src, p38alpha (MAPK14), JNK(MAPK8-10), MEK1(MAP2K1), DAG, Cyclin D1, MEK2(MAP2K2), GSK3 beta, ATP, MEK4(MAP2K4), Rac1, FARP2, Beta-catenin, Endothelin-1, Erk (MAPK1/3), Pyk2(FAK2), ATP + phosphatidylinositol 4,5-bisphosphate = ADP + phosphatidylinositol 3,4,5-trisphosphate, GRB2, H-Ras, GATA-4, AKT(PKB), Shc, <endoplasmic reticulum> Ca('2+) = <cytosol> Ca('2+), Elk-1, MEKK4(MAP3K4), c-Raf-1, Calmodulin, Adenylate cyclase, Ca('2+) endoplasmic reticulum, IP3, CaMK II, None, SOS, G-protein alpha-s, MEKK1(MAP3K1), CDC42, PtdIns(4,5)P2, G-protein alpha-q/11, PKC-epsilon, PI3K cat class IA, TCF7L2 (TCF4)
Endothelin-1 signaling via EDNRA
Endothelin-1, a potent endothelium-derived vasoconstrictor peptide, exerts a growth-promoting effect on vascular smooth muscle cells, implicating its pathogenic role in vascular remodeling. Endothelin-1 action is exerted by its binding to Endothelin receptor type A ( EDNRA ) .
EDNRA belongs to the superfamily of rhodopsin-like proteins comprising seven transmembrane-spanning regions. These proteins are involved in intracellular signaling pathways through activation of associated guanine nucleotide binding proteins (G-proteins). EDNRA is bound with G-protein alpha-s, G-protein alpha-q/11 and G-protein alpha-i family , , . The exact G-proteins and signaling cascades are not known.
Other G-proteins, G-protein alpha-q/11 and G-protein alpha-i family, a fter ENDRA stimulation by Endothelin-1 dissociate from complex with betagamma subunits, and activate any Phospholipase C beta (PLC-beta), e.g. Phospholipase C beta 3 ( PLC-beta3 ). PLC-beta3 hydrolyses of Phosphatidylinositol 4,5-bisphosphate ( Ptdins(4,5)P2 ) and the generation of Diacylglycerol ( DAG ) and Inositol trisphosphate ( IP3 ) , , . DAG and IP3 stimulate Protein kinase C, delta and epsilon ( PKC-delta and PKC-epsilon ) and mobilize intracellular Ca('2+), respectively , , , .
PKC-delta, PKC-epsilon and Ca2+ (via intermediate, presumably - Calcium/calmodulin-dependent protein kinase II ( CaMK II )) activate PTK2B protein tyrosine kinase 2 beta ( Pyk2(FAK2) )/ v-src sarcoma (Schmidt-Ruppin A-2) viral oncogene homolog ( c-Src ) complex , .
G-protein alpha-s and G-protein alpha-i may activate c-Src directly . Many Endothelin-1 -induced cascades may be activated via c-Src.
For example, c-Src phosphorylates SHC (Src homology 2 domain containing) transforming protein 1 ( Shc ). It leads to activation of Growth factor receptor-bound protein 2 ( Grb2 )/ Son of sevenless homologs ( Sos ) complex. Sos catalyzes conversion of v-Ha-ras Harvey rat sarcoma viral oncogene homolog ( H-Ras ) from GDP- to GTP-form. H-Ras -GTP is then binds to and activates v-raf-1 murine leukemia viral oncogene homolog 1 ( c-Raf-1 )/ Mitogen-activated protein kinase kinases 1 and 2 ( MEK1(MAP2K1) and MEK2(MAP2K2) )/ Mitogen activated protein kinases 3 and 1 ( ERK1/2 ) , .
Endothelin-1/ EDNRA -dependent ERK1/2 may stimulate any translation factor (e.g., ELK1, member of ETS oncogene family ( Elk-1 )), which, in turn, activates transcription of cardiac hypertrophic protein Natriuretic peptide precursor B ( BNP ) . In addition, ERK1/2 activation leads to cell proliferation , .
On the other hand, Endothelin-1/ EDNRA -activated c-Src may phosphorylate guanine-nucleotide exchange factor FERM, RhoGEF and pleckstrin domain protein 2 ( FARP2 ). FARP2 activates Cell division cycle 42 ( CDC42 )/ Mitogen-activated protein kinase kinase kinase 1 ( MEKK1(MAP3K1) )/ Mitogen-activated protein kinase kinase 4 ( MEK4(MAP2K4) )/ Mitogen-activated protein kinases 8-10 ( JNK(MAPK8-10) ) cascade. This pathway leads to inhibition of cell motility .
An unknown c-Src -activated guanine-nucleotide exchange factor (e.g., FARP2 ) stimulates Ras-related C3 botulinum toxin substrate 1 ( Rac1 )/ phosphatidylinositol 3 kinase ( PI3K )/ v-akt murine thymoma viral oncogene homolog 1 ( AKT(PKB) ). A ctivation of AKT(PKB) leads to matrix contraction . In addition, activation of the PI3K/ AKT(PKB) inhibits Glycogen synthase kinase 3 beta ( GSK-3beta ) by phosphorylation, which, in turn, leads to stabilization of the active soluble form of Catenin (cadherin-associated protein), beta 1 (Beta-catenin). Beta-catenin activates Transcription factor 7-like 2 ( TCF-4 ), which activates transcription of Cyclin D1. Moreover, Beta-catenin/ TCF-4 enhances Endothelin-1 promoter activity in a reciprocal manner. Activation of the Beta-catenin/ TCF-4 cascade by Endothelin-1 results in the proliferation and inhibits apoptosis .
Moreover, c-Src may activate Mitogen-activated protein kinase kinase kinase 4 MEKK4(MAP3K4)/ Mitogen-activated protein kinase kinase 6 ( MEK6(MAP2K6 ))/ Mitogen-activated protein kinases 14 ( p38alpha(MAPK14) ) cascade ,  via some small GTP binding proteins (e.g., CDC42). p38alpha(MAPK14) stimulate by phosphorylation GATA binding protein 4 ( GATA-4 ), and Elk-1 which in turn activates transcription of cardiac hypertrophic protein BNP , .