Receptor phosphorylation and palmitoylation are two modifications seen in C-terminus of a number of receptors in the family of G-protein coupled receptors (GPCRs). The prevalence of these two modifications suggests an important role in receptor function. Phosphorylated receptors are typically less sensitive to activation by ligand binding. However, the details of the phosphorylation mechanism in desensitization are not known. The role of palmitoylation in different receptors is less clear. Signal transduction is affected in some receptors, while receptor internalization, sequestration and phosphorylation may be affected singly or in various combination in other receptors. We propose to examine the role of phosphorylation and palmitoylation on receptor function in the rhodopsin molecule. Towards this end, we have produced rhodopsin knockout mice in which to study phosphorylation- and palmitoylation-defective rhodopsin mutants. Specifically, we will i) complete the characterization of rhodopsin hemizygous and homozygous knockout mice; ii) test the hypothesis that different rhodopsin phosphorylation sites have different physiological effects on receptor sensitivity and iii) test the hypothesis that rhodopsin palmitoylation has a role in regulating the receptor response to light stimulation. Mutant rhodopsin transgenes will be used to produce transgenic mice and cross-bred with rhodopsin knockout mice. Retinal morphology will be examined by light microscopy, and physiological function will be assessed by single cell recordings of the light evoked photoresponse. Effects on protein localization of the mutation will be assessed by immunohistochemistry. Interestingly, mutations in the C-terminus of the rhodopsin gene have been associated with the inherited human retinal degenerative disease, retinitis pigmentosa. Elucidating C-terminal domain functions that are modified by phosphorylation and palmitoylation may provide insight into defects leading to receptor dysfunctions and disease.
| Makino, Clint L; Wen, Xiao-Hong; Michaud, Norman A et al. (2012) Rhodopsin expression level affects rod outer segment morphology and photoresponse kinetics. PLoS One 7:e37832 |
| Maeda, Akiko; Okano, Kiichiro; Park, Paul S-H et al. (2010) Palmitoylation stabilizes unliganded rod opsin. Proc Natl Acad Sci U S A 107:8428-33 |
| Pang, Ji-Jie; Gao, Fan; Lem, Janis et al. (2010) Direct rod input to cone BCs and direct cone input to rod BCs challenge the traditional view of mammalian BC circuitry. Proc Natl Acad Sci U S A 107:395-400 |
| Park, Paul S-H; Sapra, K Tanuj; Jastrzebska, Beata et al. (2009) Modulation of molecular interactions and function by rhodopsin palmitylation. Biochemistry 48:4294-304 |
| Malanson, Katherine M; Lem, Janis (2009) Rhodopsin-mediated retinitis pigmentosa. Prog Mol Biol Transl Sci 88:1-31 |
| Wen, Xiao-Hong; Shen, Lixin; Brush, Richard S et al. (2009) Overexpression of rhodopsin alters the structure and photoresponse of rod photoreceptors. Biophys J 96:939-50 |
| Abd-El-Barr, Muhammad M; Pennesi, Mark E; Saszik, Shannon M et al. (2009) Genetic dissection of rod and cone pathways in the dark-adapted mouse retina. J Neurophysiol 102:1945-55 |
| Rosenzweig, Derek H; Nair, K Saidas; Wei, Junhua et al. (2007) Subunit dissociation and diffusion determine the subcellular localization of rod and cone transducins. J Neurosci 27:5484-94 |
| Brill, Elliott; Malanson, Katherine M; Radu, Roxana A et al. (2007) A novel form of transducin-dependent retinal degeneration: accelerated retinal degeneration in the absence of rod transducin. Invest Ophthalmol Vis Sci 48:5445-53 |
| Srinivasan, Vivek J; Ko, Tony H; Wojtkowski, Maciej et al. (2006) Noninvasive volumetric imaging and morphometry of the rodent retina with high-speed, ultrahigh-resolution optical coherence tomography. Invest Ophthalmol Vis Sci 47:5522-8 |
Showing the most recent 10 out of 22 publications
