Fusion between retinal rod outer segment membranes and model membranes: a role for photoreceptor peripherin/rds.
Biochemistry
; 37(26): 9477-87, 1998 Jun 30.
Article
en En
| MEDLINE
| ID: mdl-9649331
ABSTRACT
Peripherin/rds plays an essential role in the maintenance of photoreceptor rod cell disk membrane structure. The purification of this protein to homogeneity [Boesze-Battaglia, K., et al. (1997) Biochemistry 36, 6835-6846] has allowed us to characterize the functional role of peripherin/rds in the maintenance of rod outer segment (ROS) membrane fusion processes. Utilizing a cell-free fusion assay system, we report that the fusion of R18-labeled ROS plasma membrane (R18-PM) with disk membranes or peripherin/rds-enriched large unilammellar vesicles (LUVs) is inhibited upon trypsinolysis of peripherin/rds. To understand this phenomenon, we tested the ability of a series of overlapping synthetic C-terminal peripherin/rds peptides to mediate model membrane fusion. Within the 63 amino acid long region of the C-terminus, we identified a minimal 15 residue long amino acid sequence (PP-5), which is necessary to promote membrane fusion. PP-5 was able to inhibit R18-PM disk membrane fusion and promoted ANTS/DPX contents mixing in a pure vesicle system. This peptide (PP-5) promoted calcium-induced vesicle aggregation of phosphatidylethanolaminephosphatidylserine LUVs. FTIR analysis confirmed the structural prediction of this peptide as alpha-helical. When modeled as an alpha-helix, this peptide is amphiphilic with a hydrophobicity index of 0.75 and a hydrophobic moment of 0.59. PP-5 has substantial biochemical and functional homology with other well-characterized membrane fusion proteins. These results demonstrate the necessity for peripherin/rds in ROS membrane fusion, specifically the requirement for an intact C-terminal region of this protein.
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Base de datos:
MEDLINE
Asunto principal:
Segmento Externo de la Célula en Bastón
/
Glicoproteínas de Membrana
/
Proteínas del Ojo
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Proteínas de Filamentos Intermediarios
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Fusión de Membrana
/
Proteínas del Tejido Nervioso
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Biochemistry
Año:
1998
Tipo del documento:
Article