title: Novel frequenin-modulated Ca2+-signaling membrane guanylate cyclase (ROS-GC) transduction pathway in bovine hippocampus.
abstract: Frequenin is a member of the neuronal Ca(2+) sensor protein family, implicated in being the modulator of the neurotransmitter release, potassium channels, phosphatidylinositol signaling pathway and the Ca(2+)-dependent exocytosis of dense-core granules in the PC12 cells. Frequenin exhibits these biological activities through its Ca(2+) myristoyl switch, yet the switch is functionally inactive. These structural and functional traits of frequenin have been derived through the use of recombinant frequenin. In the present study, frequenin (BovFrq) native to the bovine hippocampus has been purified, sequenced for its 9 internal fragments, cloned, and studied. The findings show that structure of the BovFrq is identical to its form present in chicken, rat, mouse and human, indicating its evolutionary conservation. Its Ca(2+) myristoyl switch is active in the hippocampus. And, BovFrq physically interacts and turns on yet undisclosed ONE-GC-like ROS-GC membrane guanylate cyclase transduction machinery in the hippocampal neurons. This makes BovFrq a new Ca(2+)-sensor modulator of a novel ROS-GC transduction machinery. The study demonstrates the presence and mechanistic features of this cyclic GMP signaling pathway in the hippocampal neurons, and also provides one more support for the evolving concept where the Ca(2+)-modulated membrane guanylate cyclase transduction machinery in its variant forms is a central operational component of all neurons.
authors.affiliation: Unit of Regulatory and Molecular Biology, Departments of Cell Biology and Ophthalmology, SOM and NJMS, University of Medicine and Dentistry of New Jersey, Stratford, NJ 08084, USA.
authors.forename: Ewa
authors.initials: E
authors.lastname: Fik-Rymarkiewicz
authors.forename: Teresa
authors.initials: T
authors.lastname: Duda
authors.forename: Rameshwar K
authors.initials: RK
authors.lastname: Sharma
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D020013:Calcium Signaling; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002417:Cattle; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism*; D003001:Cloning, Molecular; D006162:Guanylate Cyclase / Q000378:metabolism*; D006624:Hippocampus / Q000201:enzymology / Q000378:metabolism*; D047468:Immunoprecipitation; D008969:Molecular Sequence Data; D051580:Neuronal Calcium-Sensor Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D009479:Neuropeptides / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D020539:Sequence Analysis, Protein
chemical_list: D002135:Calcium-Binding Proteins; D051580:Neuronal Calcium-Sensor Proteins; D009479:Neuropeptides; D011994:Recombinant Proteins; C101464:frequenin calcium sensor proteins; D006162:Guanylate Cyclase