title: Exploration of cone cyclic nucleotide-gated channel-interacting proteins using affinity purification and mass spectrometry.
abstract: Photopic (cone) vision essential for color sensation, central vision, and visual acuity is mediated by the activation of photoreceptor cyclic nucleotide-gated (CNG) channels. Naturally occurring mutations in the cone channel subunits CNGA3 and CNGB3 are associated with achromatopsia and cone dystrophies. This work investigated the functional modulation of cone CNG channel by exploring the channel-interacting proteins. Retinal protein extracts prepared from cone-dominant Nrl (- / -) mice were used in CNGA3 antibody affinity purification, followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) separation and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry analysis. The peptide mass fingerprinting of the tryptic digests and database search identified a number of proteins including spectrin alpha-2, ATPase (Na(+)/K(+) transporting) alpha-3, alpha and beta subunits of ATP synthase (H(+) transporting, mitochondrial F1 complex), and alpha-2 subunit of the guanine nucleotide-binding protein. In addition, the affinity-binding assays demonstrated an interaction between cone CNG channel and calmodulin but not cone Na(+)/Ca(2+)-K(+) exchanger in the mouse retina. Results of this study provide insight into our understanding of cone CNG channel-interacting proteins and the functional modulations.
authors.affiliation: Departments of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd., BMSB 553, 73104, Oklahoma City, OK, USA, xi-qin-ding@ouhsc.edu.
authors.forename: Xi-Qin
authors.initials: XQ
authors.lastname: Ding
authors.forename: Alexander
authors.initials: A
authors.lastname: Matveev
authors.forename: Anil
authors.initials: A
authors.lastname: Singh
authors.forename: Naoka
authors.initials: N
authors.lastname: Komori
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Matsumoto
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics; D002846:Chromatography, Affinity; D003117:Color Vision Defects / Q000503:physiopathology*; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000032:analysis / Q000302:isolation & purification / Q000502:physiology*; D005136:Eye Proteins / Q000235:genetics; D015640:Ion Channel Gating / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D054730:Protein Interaction Domains and Motifs; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D019831:Sodium-Calcium Exchanger / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; C532622:CNGB3 protein, mouse; C518237:Cnga3 protein, mouse; D054815:Cyclic Nucleotide-Gated Cation Channels; D005136:Eye Proteins; C084884:Nrl protein, mouse; D019831:Sodium-Calcium Exchanger; C074530:potassium-dependent sodium-calcium exchanger