Cytoplasmic localization of LIM-kinase 1 is directed by a short sequence within the PDZ domain

Neng Yang, Osamu Higuchi, Kensaku Mizuno

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)

Abstract

LIM-containing protein kinase 1 (LIMK1) is a serine/threonine kinase with a structure composed of two LIM domains, a PDZ domain, and a protein kinase domain. We examined the subcellular localization of LIMK1 and its variously deleted mutants in HeLa cells by transfection with these cDNAs. Immunofluorescence analysis revealed that the full-length LIMK1 and its mutants deleted with LIM domain or protein kinase domain preferentially localized in the cytoplasm, while the mutants deleted with the PDZ domain or a 52 amino acid region (B region) within the PDZ domain localized mainly in the nucleus. When the normally nuclear cyclin A was fused with the PDZ domain or the B region of LIMK1, it was localized in the cytoplasm of transfected cells. The corresponding region of the PDZ domain of postsynaptic density protein (PSD)-95 had no such function. Additionally, the PDZ domain of LIMK1 had no potential to bind to the C-terminal S/TXV peptides, to which the PSD- 95 PDZ domain can bind. Taken together these results suggest that the PDZ domain, particularly the B region, of LIMK1 has a specific function to localize the protein in the cytoplasm. When glutathione S-transferase (GST) fused with the PDZ domain of LIMK1 (GST-PDZ) or GST-PDZ deleted with the B region (GST-PDZAB) was microinjected into the nucleus of COS cells, GST-PDZ was almost completely excluded from the nucleus within 30 min, whereas GST- PDZAB remained in the nucleus. These findings suggest that the B region of LIMK1 probably has nuclear export signal activity.

Original languageEnglish
Pages (from-to)242-252
Number of pages11
JournalExperimental Cell Research
Volume241
Issue number1
DOIs
Publication statusPublished - 1998 May 25

Keywords

  • Cytoplasmic localization
  • LIM-kinase
  • Nuclear export signal
  • PDZ domain

ASJC Scopus subject areas

  • Cell Biology

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