title: Protrudin regulates endoplasmic reticulum morphology and function associated with the pathogenesis of hereditary spastic paraplegia.
abstract: Protrudin is a membrane protein that regulates polarized vesicular trafficking in neurons. The protrudin gene (ZFYVE27) is mutated in a subset of individuals with hereditary spastic paraplegia (HSP), and protrudin is therefore also referred to as spastic paraplegia (SPG) 33. We have now generated mice that express a transgene for dual epitope-tagged protrudin under control of a neuron-specific promoter, and we have subjected highly purified protrudin-containing complexes isolated from the brain of these mice to proteomics analysis to identify proteins that associate with protrudin. Protrudin was found to interact with other HSP-related proteins including myelin proteolipid protein 1 (SPG2), atlastin-1 (SPG3A), REEP1 (SPG31), REEP5 (similar to REEP1), Kif5A (SPG10), Kif5B, Kif5C, and reticulon 1, 3, and 4 (similar to reticulon 2, SPG12). Membrane topology analysis indicated that one of three hydrophobic segments of protrudin forms a hydrophobic hairpin domain similar to those of other SPG proteins. Protrudin was found to localize predominantly to the tubular endoplasmic reticulum (ER), and forced expression of protrudin promoted the formation and stabilization of the tubular ER network. The protrudin(G191V) mutant, which has been identified in a subset of HSP patients, manifested an increased intracellular stability, and cells expressing this mutant showed an increased susceptibility to ER stress. Our results thus suggest that protrudin contributes to the regulation of ER morphology and function, and that its deregulation by mutation is a causative defect in HSP.
authors.affiliation: From the Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Hashimoto
authors.forename: Michiko
authors.initials: M
authors.lastname: Shirane
authors.forename: Fumiko
authors.initials: F
authors.lastname: Matsuzaki
authors.forename: Shotaro
authors.initials: S
authors.lastname: Saita
authors.forename: Takafumi
authors.initials: T
authors.lastname: Ohnishi
authors.forename: Keiichi I
authors.initials: KI
authors.lastname: Nakayama
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D059865:Endoplasmic Reticulum Stress / Q000235:genetics; D030342:Genetic Diseases, Inborn / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D016547:Kinesins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D020125:Mutation, Missense; D010264:Paraplegia / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D040901:Proteomics; D015419:Spastic Paraplegia, Hereditary / Q000235:genetics / Q000378:metabolism; D033921:Vesicular Transport Proteins
chemical_list: D002352:Carrier Proteins; C507512:Kif5A protein, mouse; D033921:Vesicular Transport Proteins; C514783:protrudin protein, mouse; C475469:Kif5b protein, mouse; D016547:Kinesins
keywords: Endoplasmic Reticulum (ER); Endoplasmic Reticulum Stress; Membrane Structure; Neurodegenerative Diseases; Proteomics