Extracellular regulated kinase

Apelin receptors activate several signalling pathways including coupling through inhibitory G-proteins (G ) and Ras-independent activation of extracellular-regulated kinases (ERKs) via protein kinase C (PKC). The apelin receptor is one of number of G-protein-coupled receptors that can act as an alternative coreceptor for entry into cells of HIV and simian immunodeficiency vims (SIV) strains in human U87 cells expressing CD4 in vitro. Apelin peptides blocks entry of HIV but display different potencies, with apelin-36 being more effective than shorter sequences [3]. 

There are at least three major effector pathways that are activated by neurotrophic factor-Trk receptors. The best-characterized pathway is the extracellular-regulated kinase (ERK) cascade, which is regifiated by activation of Ras, a small membrane-bound G protein. Activation of Ras occurs when activated Trk receptor associates with adaptor proteins and a GTP exchange factor (see Russell and Duman 2002 for details). Ras in turn recruits and activates a serine threonine kinase, Raf, to the membrane resulting in the activation of ERK kinase (also referred to as MEK) and ERK (also known as mitogen activated protein kinase or MAPK). Activation of the Ras-Raf-MEK-ERK cascade can lead to regifiation of many celMar proteins, including ribosomal S6-kinase (RSK). 

Fig. 10.2. Components and activation of the ERK pathway. Ordering and specificity of protein kinases in the ERK pathway. ExtraceUular signals are registered via receptor tyrosine kinases and passed on to the Ras protein. Ras GTP activates protein kinases belonging to the group of MAPKK kinases (Raf kinases and MEEKs). The MAPKK kinases phosphorylate the downstream group of protein kinases, the MAPKKs at two Ser residues. The MAPKKs phosphorylate the MAPKs (ERKl and ERK2) at a Tyr and a Thr residue, and thus are classified as dual specificity kinases. MAPK mitogenic activated protein kinase ERK extracellularly regulated kinase MEK MAP/ERK kinase MAPKK MAPK kinase MAPKKK MAPKK kinase MEKK MEK kinase.

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Studies performed on human A3 AR stably transfected in CHO cells show the involvement of extracellular regulated kinase (ERK 1/2), members of the MAPK... 

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Lin SL, Johnson-Farley NN, Lubinsky DR, Cowen DS. Coupling of neuronal 5-HT7 receptors to activation of extracellular-regulated kinase through a protein kinase A-independent pathway that can utilize Epac. J Neurochem 2003 87 1076-1085. 

Andresen BT, Linnoila JJ, Jackson EK, Romero GG. 2003. Role of EGFR transactivation in angiotensin II signaling to extracellular regulated kinase in preglomerular smooth muscle cells. Hypertension 41 781-786. 

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ERK extracellular regulated kinase HIV human immunodeficiency virus... 

R.P. Brandes, R. Popp, G. Ott, D. Bredenkotter, C. Wallner, R. Busse, I. Fleming, The extracellular regulated kinases (ERK) 1/2 mediate cannabinoid-induced inhibition of gap junctional communication in endothelial cells, BrJ Pharmacol 136,709-716 (2002). 

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