TY - JOUR
T1 - Cytoplasmic localization of LIM-kinase 1 is directed by a short sequence within the PDZ domain
AU - Yang, Neng
AU - Higuchi, Osamu
AU - Mizuno, Kensaku
N1 - Funding Information:
We thank Drs. J. Pines and M. Otsubo for providing cyclin A cDNA and Dr. T. Akiyama for GST-APC cDNA. We also thank T. Amano for technical assistance, Drs. Y. Fujiki and K. Toyoshima for encouragement and helpful advice, and M. Ohara for comments on the manuscript. This work was supported by grants from the Japan Science and Technology Corporation, the Ministry of Education, Science, Sports and Culture of Japan, and Sagawa Cancer Research Foundation.
PY - 1998/5/25
Y1 - 1998/5/25
N2 - 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.
AB - 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.
KW - Cytoplasmic localization
KW - LIM-kinase
KW - Nuclear export signal
KW - PDZ domain
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U2 - 10.1006/excr.1998.4053
DO - 10.1006/excr.1998.4053
M3 - Article
C2 - 9633533
AN - SCOPUS:0031817201
VL - 241
SP - 242
EP - 252
JO - Experimental Cell Research
JF - Experimental Cell Research
SN - 0014-4827
IS - 1
ER -