Retinoschisin is a peripheral membrane protein with affinity for anionic phospholipids and affected by divalent cations.

نویسندگان

  • Camasamudram Vijayasarathy
  • Yuichiro Takada
  • Yong Zeng
  • Ronald A Bush
  • Paul A Sieving
چکیده

PURPOSE Retinoschisin (RS) is a retina-specific, secreted protein implicated in X-linked juvenile retinoschisis and essential for the structural and functional integrity of the retina. This biochemical characterization and ultrastructural localization of RS in intact murine retina was performed to further understanding of the molecular basis of its function. METHODS Subcellular fractions and fractions enriched in photoreceptor inner and outer segments were prepared from mouse retina by differential or density gradient ultracentrifugation. Immunoblot analysis was used to assess the expression of RS in various subcellular compartments and its fractionation into soluble phase on treatment of retinal cell membranes with several solubilizing reagents. RS-lipid interactions were evaluated by a protein-lipid overlay assay that used wild-type and mutant forms of RS discoidin domain glutathione S-transferase (GST) fusion proteins. The subcellular localization of RS in mouse retina was visualized by pre-embedding immunogold electron microscopy. Ultrastructure was evaluated by transmission electron microscopy. RESULTS RS was intimately associated with cell membranes of the retina. It was found to cluster on the outer leaflet of the plasma membrane of the photoreceptor inner segments, which synthesize and secrete it. It was released from the membrane at high pH, which is characteristic of a peripheral membrane protein. It was extracted from the membrane by the nonionic detergent NP-40, together with glycerophospholipids. Protein-lipid overlay assays indicated a preferential interaction between RS and anioic phospholipids. Extraction of RS from the membrane was inhibited by divalent cations. Photoreceptor inner segment morphology was markedly affected in RS(-)(/y) mice, which failed to express RS protein. CONCLUSIONS RS in intact retina is a peripheral membrane protein. Although distributed over the two membrane faces, RS is associated primarily with the outer leaflet of the inner segment plasma membrane through anionic phospholipids and divalent cations. RS's localization in photoreceptors and its biochemical properties suggest a functional role locally, at the site of secretion and membrane adhesion, in maintaining the photoreceptor inner segment stability and architecture.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Anionic Saccharides Activate Liposomes Containing Phospholipids Bearing a Boronic Acid for Ca2+-Dependent Fusion

New methods of inducing selective membrane fusion would be useful in hybridoma technology, targeted drug delivery and gene therapy.1,2 Although a number of macromolecular fusogens are known, there are very few small molecules that can trigger membrane fusion on their own.2 In certain cases, proteins, peptides, and smaller molecules can induce divalent metal cationdependent fusion processes. For...

متن کامل

Effect of Concentration of Cations on Activated Sludge Properties and Membrane Fouling in Membrane Bioreactors for Wastewater Treatment

This paper presents the results of an investigation on the effects of concentration of cations on activated sludge properties and membrane fouling in submerge membrane bioreactors. The working volume of the experimental setup was two liters. The cellulose acetate membrane was immersed in the bioreactor. The flocculability, settling properties and fouling propensity of activated sludge was measu...

متن کامل

Surface Recognition and Complexations Between Synthetic Poly(ribo)nucleotides and Neutral Phospholipids and Their Implications in Lipofection

Thermodynamic features related to preparation and use of self-assemblies formed between multilamellar and unilamellar zwitterionic liposomes and polynucleotides with various conformation and sizes are presented. The divalent metal cation or surfactant-induced adsorption, aggregation and adhesion between single- and double-stranded polyribonucleotides and phosphatidylcholine vesicles was followe...

متن کامل

Surface Recognition and Complexations Between Synthetic Poly(ribo)nucleotides and Neutral Phospholipids and Their Implications in Lipofection

Thermodynamic features related to preparation and use of self-assemblies formed between multilamellar and unilamellar zwitterionic liposomes and polynucleotides with various conformation and sizes are presented. The divalent metal cation or surfactant-induced adsorption, aggregation and adhesion between single- and double-stranded polyribonucleotides and phosphatidylcholine vesicles was followe...

متن کامل

Biosynthesis of Cyclopropane Compounds

Several natural and synthetic phospholipids can serve as substrates for the cyclopropane synthetase enzyme of Closfridium bufyricum. The conditions for optimum substrate effectiveness vary with the substrate; e.g. an anionic surfaceactive agent is necessary with phosphatidylethanolamine, while divalent cations stimulate the rate of reaction with anionic phospholipids. These variable conditions ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Investigative ophthalmology & visual science

دوره 48 3  شماره 

صفحات  -

تاریخ انتشار 2007