The retina converts light into an electrical signal through a series of biochemical steps collectively referred to as phototransduction. This signal is eventually relayed to the visual cortex of the brain, where visual perception occurs. Photoreceptor cells are able to respond to light throughout our lives because they have the ability to regenerate proteins as well as a light-sensitive chromophore. The long-term objective of our research is to elucidate the molecular reactions involved in phototransduction, including those directly involved in the regenerative capability of photoreceptor cells. Phototransduction serves as a prototype for a multitude of G protein-mediated signal transduction events initiated by activation of G protein-coupled receptors (GPCRs) and thus understanding of this process is broadly applicable to other signal transduction cascades. Our continuing investigation of phototransduction will focus on selected proteins in this pathway. Mutations in the genes encoding these particular proteins are among the main causes of blinding diseases in humans. We propose three thematically linked specific aims in this application: (1) Determine the structures of phototransduction-specific proteins and their regulation by posttranslational modifications. Understanding the 3-dimensional architecture of transduction proteins and their posttranslational modifications will yield an unparalleled wealth of atomic detail related to their function. (2) Elucidate the structural/biophysical changes involved in rhodopsin activation. Studies proposed herein will provide new biochemical and physiological insights into critical events required for receptor activation and contribute to our understanding of GPCR signaling. (3) Use pathogenic mutations of rhodopsin to determine precisely how changes in its structure affect the viability of rod photoreceptor cells. By elucidating the molecular details of abnormal cellular processing of mutated rhodopsin, we will better understand the ensuing pathology as well as develop a rational approach to alleviate retinal dystrophies related to mutations in the opsin gene.

Public Health Relevance

Phototransduction serves as a model for a multitude of G-protein-mediated signal transduction pathways initiated by activation of G-protein coupled receptors (GPCRs). Thus a more rigorous understanding of this process will have broad application to other signal transduction cascades. Therefore, the long-term objective of our research is to elucidate the detailed molecular events involved in phototransduction.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY008061-24
Application #
7754382
Study Section
Biology and Diseases of the Posterior Eye Study Section (BDPE)
Program Officer
Mariani, Andrew P
Project Start
1990-02-01
Project End
2013-12-31
Budget Start
2010-01-01
Budget End
2010-12-31
Support Year
24
Fiscal Year
2010
Total Cost
$712,692
Indirect Cost
Name
Case Western Reserve University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
077758407
City
Cleveland
State
OH
Country
United States
Zip Code
44106
Jastrzebska, Beata; Chen, Yuanyuan; Orban, Tivadar et al. (2015) Disruption of Rhodopsin Dimerization with Synthetic Peptides Targeting an Interaction Interface. J Biol Chem 290:25728-44
Hofmann, Lukas; Palczewski, Krzysztof (2015) The G protein-coupled receptor rhodopsin: a historical perspective. Methods Mol Biol 1271:3-18
Baker, Bo Y; Gulati, Sahil; Shi, Wuxian et al. (2015) Crystallization of proteins from crude bovine rod outer segments. Methods Enzymol 557:439-58
Palczewska, Grazyna; Salom, David (2015) Imaging of rhodopsin crystals with two-photon microscopy. Methods Mol Biol 1271:55-64
Palczewski, Krzysztof (2014) Chemistry and biology of the initial steps in vision: the Friedenwald lecture. Invest Ophthalmol Vis Sci 55:6651-72
Palczewska, Grazyna; Dong, Zhiqian; Golczak, Marcin et al. (2014) Noninvasive two-photon microscopy imaging of mouse retina and retinal pigment epithelium through the pupil of the eye. Nat Med 20:785-9
Chen, Yuanyuan; Jastrzebska, Beata; Cao, Pengxiu et al. (2014) Inherent instability of the retinitis pigmentosa P23H mutant opsin. J Biol Chem 289:9288-303
Tu, Xiongying; Palczewski, Krzysztof (2014) The macular degeneration-linked C1QTNF5 (S163) mutation causes higher-order structural rearrangements. J Struct Biol 186:86-94
Mustafi, Debarshi; Kikano, Sandra; Palczewski, Krzysztof (2014) Serial block face-scanning electron microscopy: a method to study retinal degenerative phenotypes. Curr Protoc Mouse Biol 4:197-204
Baker, Bo Y; Shi, Wuxian; Wang, Benlian et al. (2014) High-resolution crystal structures of the photoreceptor glyceraldehyde 3-phosphate dehydrogenase (GAPDH) with three and four-bound NAD molecules. Protein Sci 23:1629-39

Showing the most recent 10 out of 126 publications