title: Localization of Protein Kinase NDR2 to Peroxisomes and Its Role in Ciliogenesis.
abstract: Nuclear Dbf2-related (NDR) kinases, comprising NDR1 and NDR2, are serine/threonine kinases that play crucial roles in the control of cell proliferation, apoptosis, and morphogenesis. We recently showed that NDR2, but not NDR1, is involved in primary cilium formation; however, the mechanism underlying their functional difference in ciliogenesis is unknown. To address this issue, we examined their subcellular localization. Despite their close sequence similarity, NDR2 exhibited punctate localization in the cytoplasm, whereas NDR1 was diffusely distributed within the cell. Notably, NDR2 puncta mostly co-localized with the peroxisome marker proteins, catalase and CFP-SKL (cyan fluorescent protein carrying the C-terminal typical peroxisome-targeting signal type-1 (PTS1) sequence, Ser-Lys-Leu). NDR2 contains the PTS1-like sequence, Gly-Lys-Leu, at the C-terminal end, whereas the C-terminal end of NDR1 is Ala-Lys. An NDR2 mutant lacking the C-terminal Leu, NDR2(ΔL), exhibited almost diffuse distribution in cells. Additionally, NDR2, but neither NDR1 nor NDR2(ΔL), bound to the PTS1 receptor Pex5p. Together, these findings indicate that NDR2 localizes to the peroxisome by using the C-terminal GKL sequence. Intriguingly, topology analysis of NDR2 suggests that NDR2 is exposed to the cytosolic surface of the peroxisome. The expression of wild-type NDR2, but not NDR2(ΔL), recovered the suppressive effect of NDR2 knockdown on ciliogenesis. Furthermore, knockdown of peroxisome biogenesis factor genes (PEX1orPEX3) partially suppressed ciliogenesis. These results suggest that the peroxisomal localization of NDR2 is implicated in its function to promote primary cilium formation.
authors.affiliation: From the Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578.
authors.forename: Shoko
authors.initials: S
authors.lastname: Abe
authors.affiliation: From the Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Nagai
authors.affiliation: From the Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578.
authors.forename: Moe
authors.initials: M
authors.lastname: Masukawa
authors.affiliation: the Graduate School of Systems Life Sciences, Kyushu University, Motooka, Fukuoka 819-0395, and.
authors.forename: Kanji
authors.initials: K
authors.lastname: Okumoto
authors.affiliation: From the Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Homma
authors.affiliation: the Medical Institute of Bioregulation, Kyushu University, Maidashi, Fukuoka 812-8582, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Fujiki
authors.affiliation: From the Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, kmizuno@biology.tohoku.ac.jp.
authors.forename: Kensaku
authors.initials: K
authors.lastname: Mizuno
mesh_terms: D002374:Catalase / Q000378:metabolism*; D002478:Cells, Cultured; D002923:Cilia / Q000502:physiology*; D003593:Cytoplasm / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D000074435:Peroxisome-Targeting Signal 1 Receptor; D020675:Peroxisomes / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D055213:Retinal Pigment Epithelium / Q000166:cytology / Q000502:physiology*; D015398:Signal Transduction
chemical_list: C485182:Cyan Fluorescent Protein; D000074435:Peroxisome-Targeting Signal 1 Receptor; D018160:Receptors, Cytoplasmic and Nuclear; D049452:Green Fluorescent Proteins; D002374:Catalase; D017346:Protein Serine-Threonine Kinases; C496014:STK38L protein, human
keywords: NDR (nuclear dbf2-related) kinase; NDR2; cilia; ciliogenesis; peroisome targeting signal 1; peroxisome; protein kinase; protein targeting; protein translocation; serine/threonine protein kinase