title: The calcium-sensor guanylate cyclase activating protein type 2 specific site in rod outer segment membrane guanylate cyclase type 1.
abstract: The rod outer segment membrane guanylate cyclase type 1 (ROS-GC1), originally identified in the photoreceptor outer segments, is a member of the subfamily of Ca(2+)-modulated membrane guanylate cyclases. In phototransduction, its activity is tightly regulated by its two Ca(2+)-sensor protein parts, GCAP1 and GCAP2. This study maps the GCAP2-modulatory site in ROS-GC1 through the use of multiple techniques involving surface plasmon resonance binding studies with soluble ROS-GC1 constructs, coimmunoprecipitation, functional reconstitution experiments with deletion mutants, and peptide competition assays. The findings show that the sequence motif of the core GCAP2-modulatory site is Y965-N981 of ROS-GC1. The site is distinct from the GCAP1-modulatory site. It, however, partially overlaps with the S100B-regulatory site. This indicates that the Y965-N981 motif tightly controls the Ca(2+)-dependent specificity of ROS-GC1. Identification of the site demonstrates an intriguing topographical feature of ROS-GC1. This is that the GCAP2 module transmits the Ca(2+) signals to the catalytic domain from its C-terminal side and the GCAP1 module from the distant N-terminal side.
authors.affiliation: Unit of Regulatory and Molecular Biology, Department of Cell Biology SOM and NJMS, University of Medicine and Dentistry of New Jersey, Stratford, New Jersey 08084, USA.
authors.forename: Teresa
authors.initials: T
authors.lastname: Duda
authors.forename: Ewa
authors.initials: E
authors.lastname: Fik-Rymarkiewicz
authors.forename: Venkateswar
authors.initials: V
authors.lastname: Venkataraman
authors.forename: Ramalingam
authors.initials: R
authors.lastname: Krishnan
authors.forename: Karl-Wilhelm
authors.initials: KW
authors.lastname: Koch
authors.forename: Rameshwar K
authors.initials: RK
authors.lastname: Sharma
mesh_terms: D020816:Amino Acid Motifs / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive / Q000235:genetics; D019556:COS Cells; D020013:Calcium Signaling / Q000235:genetics; D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002417:Cattle; D006162:Guanylate Cyclase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D051604:Guanylate Cyclase-Activating Proteins; D047468:Immunoprecipitation; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D012374:Rod Cell Outer Segment / Q000201:enzymology*; D017384:Sequence Deletion; D020349:Surface Plasmon Resonance
chemical_list: D002135:Calcium-Binding Proteins; D051604:Guanylate Cyclase-Activating Proteins; D010446:Peptide Fragments; D011956:Receptors, Cell Surface; C110715:guanylate cyclase 1; D006162:Guanylate Cyclase