title: Two hydrophobic segments of the RTN1 family determine the ER localization and retention.
abstract: Reticulon (RTN) proteins are localized to the endoplasmic reticulum (ER), and are related to intracellular membrane trafficking, apoptosis, inhibiting axonal regeneration, and Alzheimer's disease. The RTN proteins are produced without an N-terminal signal peptide. Their C-terminal domain contains two long hydrophobic segments. We analyzed the ER localization signal of human RTN1-A. Mutant proteins lacking the first (39 residues) or second (36 residues) hydrophobic segment showed ER localization. On the other hand, the mutant lacking both hydrophobic segments was cytosolic. Enhanced green fluorescent protein (EGFP) tagged with the first or second hydrophobic segment of RTN1-A was localized to the ER. These results suggest that each hydrophobic segment determines the ER localization. In addition, EGFP tagged with the truncated form of the first hydrophobic segment exhibited the localization to the Golgi rather than the ER. This suggests that the length of the hydrophobic segment contributes to the ER retention of RTN1-A.
authors.affiliation: Division of Infectious Diseases, Department of Infectious Medicine, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka 830-0011, Japan. iwahashi@med.kurume-u.ac.jp
authors.forename: Jun
authors.initials: J
authors.lastname: Iwahashi
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Hamada
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
mesh_terms: D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D008856:Microscopy, Fluorescence; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D010957:Plasmids
chemical_list: D017931:DNA Primers; D009419:Nerve Tissue Proteins; C081781:RTN1 protein, human; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins