Disruption of two putative nuclear localization sequences is required for cytosolic localization of mitogen-activated protein kinase phosphatase-2.
MAP kinase phosphatase-2 (MKP-2) is a member of a family of dual specificity phosphatases (DSPs) that function in both the cytosol and nucleus to inactivate the MAP kinases. The mechanism that controls the subcellular distribution of these proteins is currently unclear. In this study, we have used site-directed mutagenesis to remove two novel nuclear localization sequences, NLS-1 and -2, either alone or in combination (DNLS). Loss of NLS-1 or NLS-2 alone did not alter the nuclear targeting of MKP-2 but mutation of both resulted in MKP-2 being retained within the cytosol. Furthermore, whilst expression of WT-MKP-2, NLS-1 or NLS-2 reduced both sorbitol- or UV-stimulated nuclear c-Jun N-terminal kinase (JNK) activity in HEK293 cells, this effect was absent in cells expressing DNLS-MKP-2. Similarly, transient transfection of WT-MKP-2, NLS-1 or NLS-2, but not DNLS-MKP-2 was able to substantially reduce agonist-stimulated ANF reporter activity in rat cardiac myocytes. Taken together, these results indicate that whilst both novel NLS participate in the nuclear localization of MKP-2, the expression of either sequence is sufficient to retain nuclear targeting.
Sloss
Callum M
CM
Department of Physiology and Pharmacology, Strathclyde Institute for Biomedical Sciences, Strathclyde University, 27 Taylor Street, Glasgow G4 ONR, Scotland, UK.
Cadalbert
Laurence
L
Finn
Stephen G
SG
Fuller
Stephen J
SJ
Plevin
Robin
R
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000201:enzymology; D003600:Cytosol / Q000201:enzymology; D054637:Dual-Specificity Phosphatases; D006801:Humans; D054639:Mitogen-Activated Protein Kinase Phosphatases; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D019913:Nuclear Localization Signals; D054648:Protein Phosphatase 2; D017027:Protein Tyrosine Phosphatases / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D051381:Rats
D019913:Nuclear Localization Signals; D054639:Mitogen-Activated Protein Kinase Phosphatases; D054648:Protein Phosphatase 2; C490583:DUSP4 protein, human; D054637:Dual-Specificity Phosphatases; D017027:Protein Tyrosine Phosphatases