Calmodulin regulates the translocation of Grb7 into the nucleus.
We describe in this report the presence of a nuclear localization signal (NLS) overlapping the calmodulin-binding domain (CaM-BD) of the growth factor receptor bound protein 7 (Grb7). We show that deletion of the CaM-BD of Grb7 prevents its nuclear localization, and that its Src homology 2 (SH2) domain might participate as well in the translocation process. Also, treating cells with the CaM antagonist N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) enhances the presence of Grb7 in the nucleus. We propose that CaM inhibits the translocation of Grb7 to the nucleus after binding to its CaM-BD and therefore occluding its overlapping NLS.
Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Department of Cancer Biology, Madrid, Spain.
Irene
I
García-Palmero
Antonio
A
Villalobo
D001483:Base Sequence; D002147:Calmodulin / Q000502:physiology*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D017931:DNA Primers; D051382:GRB7 Adaptor Protein / Q000378:metabolism*; D006801:Humans; D016133:Polymerase Chain Reaction; D021381:Protein Transport
D002147:Calmodulin; D017931:DNA Primers; D051382:GRB7 Adaptor Protein