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Peripherin. A rim-specific membrane protein of rod outer segment discs
Investigative Ophthalmology & Visual Science
|January 1, 1987
Summary
Researchers identified a novel bovine rod outer segment (ROS) protein, peripherin, localized to the disc rim. This protein, distinct from rhodopsin in the lamellar region, may mediate disc interactions.
Area of Science:
- Biochemistry
- Cell Biology
- Ophthalmology
Background:
- Bovine rod outer segment (ROS) disc membranes contain essential proteins for phototransduction.
- Understanding the spatial organization of these proteins is crucial for elucidating visual processes.
Purpose of the Study:
- To identify and localize novel membrane proteins within bovine ROS disc membranes.
- To characterize a protein found at the periphery of ROS discs.
Main Methods:
- Radioimmune assays and immunocytochemical techniques were employed.
- Monoclonal antibodies (mAbs) 3B6 and 2B6 were used to probe ROS membrane proteins separated by SDS-PAGE.
- Immunogold-dextran labeling was utilized for high-resolution localization studies on ROS sections and isolated discs.
Main Results:
- Two mAbs, 3B6 and 2B6, identified a protein with apparent molecular weights of 33,000 daltons (reduced) and a doublet of 67,000/69,000 daltons (non-reduced).
- Immunogold labeling localized this protein to the periphery of ROS discs, near the plasma membrane, leading to its designation as 'peripherin'.
- Antirhodopsin mAbs showed dense labeling in the lamellar region, contrasting with peripherin's peripheral localization, suggesting distinct membrane domains.
Conclusions:
- Peripherin is a high molecular weight protein localized to the rim region of ROS discs.
- The distinct localization of peripherin and rhodopsin supports the concept of specialized membrane domains within ROS discs.
- Peripherin may play a role in disc-disc and disc-plasma membrane interactions.