Biomaterial Database

IP3-independent signalling of OX1 orexin/hypocretin receptors to Ca2+ influx and ERK. 2007

Marie E Ekholm, and Lisa Johansson, and Jyrki P Kukkonen

Department of Neuroscience, Division of Physiology, Uppsala University, BMC, PO Box 572, SE-75123 Uppsala, Sweden.

OX1 orexin receptors (OX1R) have been shown to activate receptor-operated Ca2+ influx pathways as their primary signalling pathway; however, investigations are hampered by the fact that orexin receptors also couple to phospholipase C, and therewith inositol-1,4,5-trisphosphate (IP3)-dependent Ca2+ release. We have here devised a method to block the latter signalling in order to focus on the mechanism of Ca2+ influx activation by OX1R in recombinant systems. Transient expression of the IP3-metabolising enzymes IP3-3-kinase-A (inositol-1,4,5-trisphosphate-->inositol-1,3,4,5-tetrakisphosphate) and type I IP3-5-phosphatase (inositol-1,4,5-trisphosphate-->inositol-1,4-bisphosphate) almost completely attenuated the OX1R-stimulated IP3 elevation and Ca2+ release from intracellular stores. Upon attenuation of the IP3-dependent signalling, the receptor-operated Ca2+ influx pathway became the only source for Ca2+ elevation, enabling mechanistic studies on the receptor-channel coupling. Attenuation of the IP3 elevation did not affect the OX1R-mediated ERK (extracellular signal-regulated kinase) activation in CHO cells, which supports our previous finding of the major importance of receptor-operated Ca2+ influx for this response.

UI	MeSH Term	Description	Entries
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D003412	Cricetulus	A genus of the family Muridae consisting of eleven species. C. migratorius, the grey or Armenian hamster, and C. griseus, the Chinese hamster, are the two species used in biomedical research.	Hamsters, Armenian,Hamsters, Chinese,Hamsters, Grey,Armenian Hamster,Armenian Hamsters,Chinese Hamster,Chinese Hamsters,Grey Hamster,Grey Hamsters,Hamster, Armenian,Hamster, Chinese,Hamster, Grey
D006224	Cricetinae	A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.	Cricetus,Hamsters,Hamster
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D015398	Signal Transduction	The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.	Cell Signaling,Receptor-Mediated Signal Transduction,Signal Pathways,Receptor Mediated Signal Transduction,Signal Transduction Pathways,Signal Transduction Systems,Pathway, Signal,Pathway, Signal Transduction,Pathways, Signal,Pathways, Signal Transduction,Receptor-Mediated Signal Transductions,Signal Pathway,Signal Transduction Pathway,Signal Transduction System,Signal Transduction, Receptor-Mediated,Signal Transductions,Signal Transductions, Receptor-Mediated,System, Signal Transduction,Systems, Signal Transduction,Transduction, Signal,Transductions, Signal
D016466	CHO Cells	CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.	CHO Cell,Cell, CHO,Cells, CHO
D043562	Receptors, G-Protein-Coupled	The largest family of cell surface receptors involved in SIGNAL TRANSDUCTION. They share a common structure and signal through HETEROTRIMERIC G-PROTEINS.	G Protein Coupled Receptor,G-Protein-Coupled Receptor,G-Protein-Coupled Receptors,G Protein Coupled Receptors,Receptor, G-Protein-Coupled,Receptors, G Protein Coupled
D048049	Extracellular Signal-Regulated MAP Kinases	A mitogen-activated protein kinase subfamily that is widely expressed and plays a role in regulation of MEIOSIS; MITOSIS; and post mitotic functions in differentiated cells. The extracellular signal regulated MAP kinases are regulated by a broad variety of CELL SURFACE RECEPTORS and can be activated by certain CARCINOGENS.	ERK MAP Kinase,ERK MAP Kinases,Extracellular Signal-Regulated Kinase,Extracellular Signal-Regulated Kinases,Extracellular Signal-Regulated MAP Kinase,MAP Kinases, Extracellular Signal-Regulated,Extracellular Signal Regulated Kinase,Extracellular Signal Regulated Kinases,Extracellular Signal Regulated MAP Kinase,Extracellular Signal Regulated MAP Kinases,Kinase, ERK MAP,Kinase, Extracellular Signal-Regulated,Kinases, Extracellular Signal-Regulated,MAP Kinase, ERK,MAP Kinases, Extracellular Signal Regulated,Signal-Regulated Kinase, Extracellular
D053496	Inositol 1,4,5-Trisphosphate Receptors	Intracellular receptors that bind to INOSITOL 1,4,5-TRISPHOSPHATE and play an important role in its intracellular signaling. Inositol 1,4,5-trisphosphate receptors are calcium channels that release CALCIUM in response to increased levels of inositol 1,4,5-trisphosphate in the CYTOPLASM.	Inositol 1,4,5-Triphosphate Receptor,Inositol 1,4,5-Triphosphate Receptors,Inositol 1,4,5-Trisphosphate Receptor,1,4,5-INTP Receptor,INSP3 Receptor,INSP3 Receptor Type 1,INSP3 Receptor Type 2,INSP3 Receptor Type 3,IP3 Receptor,Inositol 1,4,5-trisphosphate Receptor Subtype 3,Inositol 1,4,5-trisphosphate Receptor Type 1,Inositol 1,4,5-trisphosphate Receptor Type 2,Inositol 1,4,5-trisphosphate Receptor Type 3,Inositol Triphosphate Receptor,Inositol-1,4,5-Triphosphate Receptor,Receptor, Inositol-1,4,5-triphosphate,Type 1 Inositol 1,4,5-trisphosphate Receptor,Type 3 Inositol 1,4,5-trisphosphate Receptor,Receptor, INSP3,Receptor, IP3,Receptor, Inositol Triphosphate,Triphosphate Receptor, Inositol
D018013	Receptors, Neuropeptide	Cell surface receptors that bind specific neuropeptides with high affinity and trigger intracellular changes influencing the behavior of cells. Many neuropeptides are also hormones outside of the nervous system.	Neuropeptide Receptors,Neuropeptide Receptor,Receptors, Neuropeptides,Neuropeptides Receptors,Receptor, Neuropeptide