Associate Professor, Department of Cell Biology
Ph.D., Lund University, Lund, Sweden
Association for Research in Vision and Ophthalmology (ARVO)
International Society for Eye Research (ISER)
American Chemical Society (ACS)
Mechanism of photoreceptor degeneration in CNG channel deficiency. Cone phototransduction mediated by photoreceptor cyclic nucleotide-gated (CNG) channel activation is essential for central and color vision and visual acuity. Mutations in the cone CNG channel subunits CNGA3 and CNGB3 are highly linked to various forms of achromatopsia, progressive cone dystrophy, and some maculopathies. The underlying mechanism and retinal pathogenesis remain unclear. We are interested in investigating the molecular mechanism of cone degeneration in CNG channel deficiency using mouse models.
Biochemical characterization of cone CNG channel complex. Proper channel subunit association and complex assembly are essential for CNG channel function. Using cone-dominant mouse models, we wish to determine the molecular basis of channel subunit interaction and stoichiometry of the channel complex and explore the channel modulation by identifying its interacting proteins.
Arjun Thapa, Lynsie Morris, Jianhua Xu, Hongwei Ma, Stylianos Michalakis, Martin Biel and Xi-Qin Ding. Endoplasmic Reticulum Stress-associated Cone Photoreceptor Degeneration in Cyclic Nucleotide-gated Channel Deficiency. J Biol Chem. 2012, 287(22):18018-29. PMCID: PMC3365688.
Jianhua Xu, Lynsie M. Morris, Stylianos Michalakis, Martin Biel, Steven J. Fliesler, David M. Sherry and Xi-Qin Ding. CNGA3 Deficiency Affects Cone Synaptic Terminal Structure and Function and Leads to Secondary Rod Dysfunction and Degeneration. Invest Ophthalmol. Vis. Sci. 2012, 53:1117-29. PMCID: PMC3339899.
Livia S Carvalho, Jianhua Xu, Rachael A Pearson, Alexander J Smith, James W Bainbridge, Lynsie M Morris, Steven J Fliesler, Xi-Qin Ding and Robin R Ali. Long-term and Age-dependent Restoration of Visual Function in A Mouse Model of CNGB3-associated Achromatopsia following Gene Therapy. Human Molecular Genetics 2011, 20(16):3161-75. PMCID: PMC3140821.
Jianhua Xu, Lynsie Morris, Steven J. Fliesler, David M. Sherry, and Xi-Qin Ding. Early Onset, Slow Progression of Cone Photoreceptor Dysfunction and Degeneration in CNG Channel Subunit CNGB3 Deficiency. Invest Ophthalmol. Vis. Sci. 2011, 52(6):3557-66. PMCID: PMC3109041.
Alexander V. Matveev, J. Browning Fitzgerald, Jianhua Xu, Anna P. Malykhina, Karla K. Rodgers, and Xi-Qin Ding. The Disease-Causing Mutations in the Carboxyl-Terminus of Cone Cyclic Nucleotide-Gated Channel CNGA3 Subunit Alter the Local Secondary Structure and Interfere with the Channel Active Conformational Change. Biochemistry, 2010, 49(8):1628-39. PMCID: PMC2829136.
Xi-Qin Ding, Cynthia S. Harry, Umino Y, Alexander V. Matveev, Steven J. Fliesler and Robert B. Barlow. Impaired Cone Function and Cone Degeneration Resulting from CNGB3 Deficiency: Down-regulation of CNGA3 Biosynthesis as a Potential Mechanism. Human Molecular Genetics 2009, 18(24):4770-4780. PMCID: PMC2778372.
Xi-Qin Ding, Alexander B. Quiambao, J. Browning Fitzgerald, Mark J. Cooper, Shannon M. Conley, and Muna I. Naash. Ocular Delivery of Compacted DNA-Nanoparticles Does Not Elicit Toxicity in the Mouse Retina. PLoS ONE, 2009, e7410. PMCID: PMC2756629.
Dibyendu Chakraborty, Xi-Qin Ding, Shannon M. Conley, Steve J. Fliesler, and Muna I. Naash. Differential Requirements for Rds Intermolecular Disulfide-Linked Oligomerization in Rods Versus Cones. Human Molecular Genetics, 2009 18(5):797-808. PMCID: PMC2640204.
Alexander V. Matveev, Alexander B. Quiambao, J. Browning Fitzgerald and Xi-Qin Ding. Native Cone Photoreceptor Cyclic Nucleotide-Gated Channel Is A Heterotetrameric Complex Comprising both CNGA3 and CNGB3: A Study Using the Cone-Dominant Retina of Nrl-/- Mice. Journal of Neurochemistry, 2008, 106:2042-2055. PMCID: PMC2756101.
Xi-Qin Ding, J. Browning Fitzgerald, Alexander V. Mateev, Mark E. McClellan, and Michael H. Elliott. Functional Activity of Photoreceptor Cyclic Nucleotide-Gated Channels Is Dependent on the Integrity of Cholesterol and Sphingolipid-enriched Membrane Domains. Biochemistry 2008, 47 (12):3677-87.
University of Oklahoma Health Sciences Center
Department of Cell Biology
P.O. Box 26901
Oklahoma City, OK 73126-0901
Phone: (405) 271-8001 ext. 47966
Fax: (405) 271-3548