DEPARTMENT OF VISION SCIENCES
Steven Jay Pittler, Ph.D.
Professor, Vision Sciences
Contact Information:
Office - (205) 934-6744
Physical Address:
658 Worrell Building
924 18th Street South
Mailing Address:
WORB 658
1530 Third Avenue South
Birmingham, AL 35294-4390
Biographical Sketch:
Education:
B.S. - Michigan State University
Ph.D. - Michigan State University
Administrative Responsibilities:
Chair, Vision Sciences Faculty Advisory Committee
Director, Vision Science Research Center Molecular Biology & Physiology Core Module
Chair, Vision Science Graduate Program Curriculum Committee
Secondary Appointments:
Professor, Ophthalmology
Professor, Biochemistry and Molecular Genetics
Senior Scientist Vision Sciences Research Center
Senior Scientist Arthritis and Musculoskeletal Disease Center
Personal:
I spend most of my off time as a community leader and participating in activities with my family. I like golf and tennis and international travel.
Scholarly Activity:
Teaching:
VIS 744. Molecular Biology, Biochemistry and Physiology of the Eye. This course provides an overview of diverse fields covering all aspects both the anterior and posterior segments
VIS 745. Molecular Biology, Biochemistry and Physiology of the Eye. This course continues and completes the overview of diverse fields covering all aspects both the anterior and posterior segments begun in VIS 744.
VS 111 Biochemistry of the Eye This course covers the Biochemistry and Molecular Biology of the Eye geared towards the needs of the professional Optometry student.
Research:
Research in Dr. Pittler's laboratory focuses on the biochemistry and molecular biology of photoreceptor cells. Within these cells the initial events mediating vision occur. Light is absorbed in the photoreceptors by the receptor molecule, rhodopsin (R) which then activates another protein, transducin (T). Transducin activates a third protein, cGMP phosphodiesterase (PDE) that leads to the hydrolysis of cyclic guanosine monophosphate (cGMP). The drop in cGMP levels closes a cGMP-gated cation channel in the plasma membrane triggering the formation of an electrical impulse that is transmitted to the brain. Guanylate cyclase (GC) mediates the return to the dark state by replenishing the cGMP levels. Other ancillary proteins regulate the system to allow a response over 8 orders of magnitude of light intensity.
The retina is comprised of several layers of cells; the ganglion cell layer (GCL) is oriented towards the center of the eye. These cells have long axons that traverse the retina and extend back to the brain. The inner plexiform layer (IPL) consists of synaptic connections between ganglion cells and inner retinal neurons. The inner nuclear layer consists of the nuclei of the inner retinal cells. The outer segment (OS), inner segment (IS) and outer nuclear layer (ONL) is comprised of the corresponding segments of photoreceptor cells. The phototransduction process that initiates vision is active in the photoreceptor outer segments.
The current primary focus in my laboratory is on the biochemistry, cell biology and molecular biology of the cGMP-gated cation channel of the rod photoreceptor. This channel consists of two related subunits (alpha and beta) in a tetrameric complex consisting of 1 beta and 3 alpha subunits. The beta subunit appears to be a modulatory subunit of the activity that is observed with the alpha subunit alone. We are focusing on the beta subunit gene which is very complex encoding multiple transcripts that are likely to be initiated by multiple promoters. We have generated a knockout of the gene in mice and have found that the beta subunit is required for normal functional expression of the channel and that both the beta subunit and a related GARP protein expressed from the same gene are required for outer segment structural integrity. We are currently working on further characterization of the structural roles of the beta subunit and GARP proteins.
A second focus of the laboratory is a translational approach to the treatment of a defined group of hereditary retinal disorders collectively known as retinitis pigmentosa (RP). Classic RP presents with night blindness, attenuated retinal vessels, bone-spicule like pigmentation, and narrowed visual fields. We are working with a new class of compounds that has been shown to promote readthrough of premature stop codons. We are testing the potential to use this class of compounds as a novel molecular drug treatment to restore vision to the 5-15% subset of RP that is due to nonsense mutations.
Publications
Additional Information:
Previous positions:
Baylor College of Medicine, Research Instructor 1991-1992
University of South Alabama Professor of Biochemistry & Molecular Biology 1992-1999
University of South Alabama Director, Center for Eye Research 1995-1999