title: SNAREs Interact with Retinal Degeneration Slow and Rod Outer Segment Membrane Protein-1 during Conventional and Unconventional Outer Segment Targeting.
abstract: Mutations in the photoreceptor protein peripherin-2 (also known as RDS) cause severe retinal degeneration. RDS and its homolog ROM-1 (rod outer segment protein 1) are synthesized in the inner segment and then trafficked into the outer segment where they function in tetramers and covalently linked larger complexes. Our goal is to identify binding partners of RDS and ROM-1 that may be involved in their biosynthetic pathway or in their function in the photoreceptor outer segment (OS). Here we utilize several methods including mass spectrometry after affinity purification, in vitro co-expression followed by pull-down, in vivo pull-down from mouse retinas, and proximity ligation assay to identify and confirm the SNARE proteins Syntaxin 3B and SNAP-25 as novel binding partners of RDS and ROM-1. We show that both covalently linked and non-covalently linked RDS complexes interact with Syntaxin 3B. RDS in the mouse is trafficked from the inner segment to the outer segment by both conventional (i.e., Golgi dependent) and unconventional secretory pathways, and RDS from both pathways interacts with Syntaxin3B. Syntaxin 3B and SNAP-25 are enriched in the inner segment (compared to the outer segment) suggesting that the interaction with RDS/ROM-1 occurs in the inner segment. Syntaxin 3B and SNAP-25 are involved in mediating fusion of vesicles carrying other outer segment proteins during outer segment targeting, so could be involved in the trafficking of RDS/ROM-1.
authors.affiliation: Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, United States of America.
authors.forename: Rahel
authors.initials: R
authors.lastname: Zulliger
authors.affiliation: Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, United States of America.
authors.forename: Shannon M
authors.initials: SM
authors.lastname: Conley
authors.affiliation: Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, United States of America.
authors.forename: Maggie L
authors.initials: ML
authors.lastname: Mwoyosvi
authors.affiliation: Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, United States of America.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Stuck
authors.affiliation: Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, United States of America.
authors.forename: Seifollah
authors.initials: S
authors.lastname: Azadi
authors.affiliation: Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, United States of America.
authors.forename: Muna I
authors.initials: MI
authors.lastname: Naash
mesh_terms: D000818:Animals; D005136:Eye Proteins / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D013058:Mass Spectrometry / Q000379:methods; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D064531:Peripherins / Q000378:metabolism*; D050765:Qa-SNARE Proteins / Q000302:isolation & purification / Q000378:metabolism*; D055214:Retinal Photoreceptor Cell Outer Segment / Q000378:metabolism*; D015398:Signal Transduction; D050825:Synaptosomal-Associated Protein 25 / Q000302:isolation & purification / Q000378:metabolism*; D059470:Tetraspanins
chemical_list: D005136:Eye Proteins; D008565:Membrane Proteins; D064531:Peripherins; C578996:Prph2 protein, mouse; D050765:Qa-SNARE Proteins; C081477:Rom1 protein, mouse; C494209:Snap25 protein, mouse; D050825:Synaptosomal-Associated Protein 25; D059470:Tetraspanins