title: Directionality in protein translocation across membranes: the N-tail phenomenon.
abstract: Protein translocation normally starts from an N-terminal signal peptide and proceeds in an N-to-C-terminal direction. However, in certain integral membrane proteins an N-terminal tail is translocated even though it is not preceded by a signal peptide. In eukaryotic cells this process involves the normal Sec-machinery. In contrast, recent studies in Escherichia coli show that translocation of such N-terminal tails occurs by a mechanism that does not appear to involve the Sec proteins and is most efficient for short tails lacking positively charged residues. These novel observations suggest that the Sec-machinery has an inherent N-to-C-terminal directionality and cannot work 'in reverse'.
authors.affiliation: Dept of Chemistry, Ohio State University, Columbus 43210, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Dalbey
authors.forename: A
authors.initials: A
authors.lastname: Kuhn
authors.forename: G
authors.initials: G
authors.lastname: von Heijne