Nuclear import of LASP-1 is regulated by phosphorylation and dynamic protein-protein interactions.
LASP-1 is a multidomain protein predominantly localized at focal contacts, where it regulates cytoskeleton dynamics and cell migration. However, in different tumor entities, a nuclear LASP-1 accumulation is observed, thought to have an important role in cancer progression. Until now, the molecular mechanisms that control LASP-1 nuclear import were not elucidated. Here, we identified a novel LASP-1-binding partner, zona occludens protein 2 (ZO-2), and established its role in the signal transduction pathway of LASP-1 nucleo-cytoplasmatic shuttling. Phosphorylation of LASP-1 by PKA at serine 146 induces translocation of the LASP-1/ZO-2 complex from the cytoplasm to the nucleus. Interaction occurs within the carboxyterminal proline-rich motif of ZO-2 and the SH3 domain in LASP-1. In situ proximity ligation assay confirmed the direct binding between LASP-1 and ZO-2 and visualized the shuttling. Nuclear export is mediated by Crm-1 and a newly identified nuclear export signal in LASP-1. Finally, dephosphorylation of LASP-1 by phosphatase PP2B is suggested to relocalize the protein back to focal contacts. In summary, we define a new pathway for LASP-1 in tumor progression.
Institute of Clinical Biochemistry and Pathobiochemistry, University Clinic of Wuerzburg, Wuerzburg, Germany.
S
S
Mihlan
C
C
Reiß
P
P
Thalheimer
S
S
Herterich
S
S
Gaetzner
J
J
Kremerskothen
H J
HJ
Pavenstädt
U
U
Lewandrowski
A
A
Sickmann
E
E
Butt
D021581:Active Transport, Cell Nucleus; D048868:Adaptor Proteins, Signal Transducing / Q000096:biosynthesis / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000096:biosynthesis / Q000378:metabolism*; D006801:Humans; D060588:LIM Domain Proteins / Q000096:biosynthesis / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D015398:Signal Transduction; D062827:Zonula Occludens-2 Protein / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D003598:Cytoskeletal Proteins; C096353:LASP1 protein, human; D060588:LIM Domain Proteins; C569046:TJP2 protein, human; D062827:Zonula Occludens-2 Protein; D017868:Cyclic AMP-Dependent Protein Kinases