The SUMO-specific isopeptidase SENP2 associates dynamically with nuclear pore complexes through interactions with karyopherins and the Nup107-160 nucleoporin subcomplex.
The association of small, ubiquitin-related modifier-specific isopeptidases (also known as sentrin-specific proteases, or SENPs) with nuclear pore complexes (NPCs) is conserved in eukaryotic organisms ranging from yeast to mammals. However, the functional significance of this association remains poorly understood, particularly in mammalian cells. In this study, we have characterized the molecular basis for interactions between SENP2 and NPCs in human cells. Using fluorescence recovery after photobleaching, we demonstrate that SENP2, although concentrated at the nuclear basket, is dynamically associated with NPCs. This association is mediated by multiple targeting elements within the N-terminus of SENP2 that function cooperatively to mediate NPC localization. One of these elements consists of a high-affinity nuclear localization signal that mediates indirect tethering to FG-repeat-containing nucleoporins through karyopherins. A second element mediates interactions with the Nup107-160 nucleoporin subcomplex. A third element consists of a nuclear export signal. Collectively, our findings reveal that SENP2 is tethered to NPCs through a complex interplay of interactions with nuclear import and export receptors and nucleoporins. Disruption of these interactions enhances SENP2 substrate accessibility, suggesting an important regulatory node in the SUMO pathway.
Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA.
Jacqueline
J
Goeres
Pak-Kei
PK
Chan
Debaditya
D
Mukhopadhyay
Hong
H
Zhang
Brian
B
Raught
Michael J
MJ
Matunis
D021581:Active Transport, Cell Nucleus / Q000502:physiology; D020816:Amino Acid Motifs; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D028884:Karyopherins / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D019913:Nuclear Localization Signals / Q000235:genetics / Q000378:metabolism*; D022022:Nuclear Pore / Q000235:genetics / Q000378:metabolism*; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D025842:SUMO-1 Protein / Q000235:genetics / Q000378:metabolism
D028884:Karyopherins; D046912:Multiprotein Complexes; C512772:NUP107 protein, human; C440251:NUP160 protein, human; D019913:Nuclear Localization Signals; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D025842:SUMO-1 Protein; D003546:Cysteine Endopeptidases; C501833:SENP2 protein, human