title: A novel mode of translocation for cytolethal distending toxin.
abstract: Thermal instability in the toxin catalytic subunit may be a common property of toxins that exit the endoplasmic reticulum (ER) by exploiting the mechanism of ER-associated degradation (ERAD). The Haemophilus ducreyi cytolethal distending toxin (HdCDT) does not utilize ERAD to exit the ER, so we predicted the structural properties of its catalytic subunit (HdCdtB) would differ from other ER-translocating toxins. Here, we document the heat-stable properties of HdCdtB which distinguish it from other ER-translocating toxins. Cell-based assays further suggested that HdCdtB does not unfold before exiting the ER and that it may move directly from the ER lumen to the nucleoplasm. These observations suggest a novel mode of ER exit for HdCdtB.
authors.affiliation: Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Lina
authors.initials: L
authors.lastname: Guerra
authors.forename: Kathleen N
authors.initials: KN
authors.lastname: Nemec
authors.forename: Shane
authors.initials: S
authors.lastname: Massey
authors.forename: Suren A
authors.initials: SA
authors.lastname: Tatulian
authors.forename: Monica
authors.initials: M
authors.lastname: Thelestam
authors.forename: Teresa
authors.initials: T
authors.lastname: Frisan
authors.forename: Ken
authors.initials: K
authors.lastname: Teter
mesh_terms: D001427:Bacterial Toxins / Q000378:metabolism*; D002942:Circular Dichroism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006191:Haemophilus ducreyi / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D018613:Microscopy, Confocal; D017510:Protein Folding; D021381:Protein Transport
chemical_list: D001427:Bacterial Toxins; C067044:cytolethal distending toxin