title: A Tripartite Structure of the Signals that Determine Protein Insertion into the Endoplasmic Reticulum Membrane creator: Haeuptle, Marie-Theres creator: Flint, Nicholas creator: Gough, Nicholas M. creator: Dobberstein, Bernhard subject: ddc-570 subject: 570 Life sciences description: Multilineage colony stimulating factor is a secretory protein with a cleavable signal sequence that is unusually long and hydrophobic. Using molecular cloning techniques we exchanged sequences NH2- or COOH-terminally flanking the hydrophobic signal sequence. Such modified fusion proteins still inserted into the membrane but their signal sequence was not cleaved. Instead the proteins were now anchored in the membrane by the formerly cleaved signal sequence (signal-anchor sequence). They exposed the NH2 terminus on the exoplasmic and the COOH terminus on the cytoplasmic side of the membrane. We conclude from our results that hydrophilic sequences flanking the hydrophobic core of a signal sequence can determine cleavage by signal peptidase and insertion into the membrane. It appears that negatively charged amino acid residues close to the NH2 terminal side of the hydrophobic segment are compatible with translocation of this segment across the membrane. A tripartite structure is proposed for signal-anchor sequences: a hydrophobic core region that mediates targeting to and insertion into the ER membrane and flanking hydrophilic segments that determine the orientation of the protein in the membrane. date: 1989 type: Article type: info:eu-repo/semantics/article type: NonPeerReviewed format: application/pdf identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/8473/1/Haeuptle_1989_JCB.pdf identifier: DOI:10.11588/heidok.00008473 identifier: urn:nbn:de:bsz:16-opus-84737 identifier: Haeuptle, Marie-Theres ; Flint, Nicholas ; Gough, Nicholas M. ; Dobberstein, Bernhard (1989) A Tripartite Structure of the Signals that Determine Protein Insertion into the Endoplasmic Reticulum Membrane. The Journal of Cell Biology, 108. pp. 1227-1236. relation: https://archiv.ub.uni-heidelberg.de/volltextserver/8473/ rights: info:eu-repo/semantics/openAccess rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html language: eng