A monopartite nuclear localization sequence regulates nuclear targeting of the actin binding protein myopodin.
Myopodin is an actin bundling protein that shuttles between nucleus and cytoplasm in response to cell stress or during differentiation. Here, we show that the myopodin sequence 58KKRRRRARK66, when tagged to either enhanced green fluorescent protein (EGFP) or to enhanced cyan fluorescent protein-CapG (ECFPCapG), is able to target these proteins to the nucleolus in HeLa or HEK293T cells. By contrast, 58KKRR61-ECFP-CapG accumulates in the nucleus. Mutation of 58KKRRRRARK66 into alanine residues blocks myopodin nuclear import and promotes formation of cytoplasmic actin filaments. A second putative nuclear localization sequence, 612KTSKKKGKK620, displays much weaker activity in a heterologous context, and appears not to be functional in the full length protein. Thus myopodin nuclear translocation is dependent on a monopartite nuclear localization sequence.
De Ganck
Ariane
A
Department of Medical Protein Research, Flanders Interuniversity Institute for Biotechnology (V.I.B.), Ghent University, Faculty of Medicine and Health Sciences, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.
Hubert
Thomas
T
Van Impe
Katrien
K
Geelen
Danny
D
Vandekerckhove
Joël
J
De Corte
Veerle
V
Gettemans
Jan
J
D021581:Active Transport, Cell Nucleus; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D002460:Cell Line; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D008840:Microfilament Proteins / Q000378:metabolism*; D019913:Nuclear Localization Signals / Q000502:physiology*
C485182:Cyan Fluorescent Protein; D008840:Microfilament Proteins; D019913:Nuclear Localization Signals; C503979:SYNPO2 protein, human; D049452:Green Fluorescent Proteins