title: SUMO unloads the Kap114 cab.
abstract: Nucleocytoplasmic transport is an essential mechanism in all eukaryotic cells, for which the basic mechanisms seemed well understood. Transport receptors of the importin b/karyopherin family recognize, translocate and discharge cargo. Key to directed transport is the GTPase Ran, which determines compartment-specific interactions between receptors and their cargo. In this issue of The EMBO Journal, Rothenbusch et al (2012) now add a new energy-dependent event to this basic pathway by providing direct evidence that the posttranslational modification of the yeast import receptor Kap114 with small ubiquitin-related modifier (SUMO) is indispensable for its correct function. An exciting model emerges in which Kap114 sumoylation regulates Ran-dependent cargo release, and thereby acts as a mechanism for intranuclear targeting of the import cargo.
authors.affiliation: Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Werner
authors.forename: Frauke
authors.initials: F
authors.lastname: Melchior
mesh_terms: D021581:Active Transport, Cell Nucleus; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D058207:Sumoylation; D028961:beta Karyopherins / Q000378:metabolism*
chemical_list: C400425:KAP114 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D028961:beta Karyopherins