TWIN SISTER of FT (TSF) interacts with FRUCTOKINASE6 and inhibits its kinase activity in arabidopsis

Suhyun Jin, Sunyoung Kim, Ji Hoon Ahn

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

In flowering plants, the developmental switch to the reproductive phase is tightly regulated and involves the integration of internal and external signals. FLOWERING LOCUS T (FT) and TWIN SISTER OF FT (TSF) integrate signals from multiple pathways. FT and TSF function as florigenic substances, and share high sequence similarity with mammalian Raf kinase inhibitor protein (RKIP). Despite their strong similarity to RKIP, the kinase inhibitory activity of FT and TSF remains to be investigated. We performed a yeast two-hybrid screen and found that TSF interacted with FRUCTOKINASE6 (FRK6), which phosphorylates fructose for various metabolic pathways. Among the seven Arabidopsis FRKs, FRK6 and FRK7 have high sequence similarity; therefore, we investigated whether TSF interacts with FRK6 and FRK7. In vitro pull-down assays and bimolecular fluorescence complementation assays revealed that TSF interacts with FRK6 in the nucleus, but not with FRK7. Kinase activity assays suggested that TSF inhibits the kinase activity of FRK6, whereas FT does not. By contrast, neither TSF nor FT inhibits the kinase activity of FRK7. The frk6 and frk7 mutants show slightly delayed flowering, but only under short-day (SD) conditions. Plastochron length is also affected in both frk6 and frk7 mutants under SD conditions. FT expression levels decreased in frk6 mutants, but not in frk7 mutants. Taken together, our findings suggest that TSF physically interacts with FRK6 and affects its kinase activity, whereas FT does not, although these proteins share high sequence similarity.

Original languageEnglish
Article number1807
JournalFrontiers in Plant Science
Volume8
DOIs
Publication statusPublished - 2017 Oct 18

Fingerprint

phosphotransferases (kinases)
Arabidopsis
mutants
assays
protein kinases
biochemical pathways
fructose
Angiospermae
proteins
fluorescence
yeasts
flowering

Keywords

  • Arabidopsis
  • FRK6
  • Fructokinase
  • FT
  • Kinase activity
  • TSF

ASJC Scopus subject areas

  • Plant Science

Cite this

TWIN SISTER of FT (TSF) interacts with FRUCTOKINASE6 and inhibits its kinase activity in arabidopsis. / Jin, Suhyun; Kim, Sunyoung; Ahn, Ji Hoon.

In: Frontiers in Plant Science, Vol. 8, 1807, 18.10.2017.

Research output: Contribution to journalArticle

@article{20ee47bde38c49c9886d610f786a3b8d,
title = "TWIN SISTER of FT (TSF) interacts with FRUCTOKINASE6 and inhibits its kinase activity in arabidopsis",
abstract = "In flowering plants, the developmental switch to the reproductive phase is tightly regulated and involves the integration of internal and external signals. FLOWERING LOCUS T (FT) and TWIN SISTER OF FT (TSF) integrate signals from multiple pathways. FT and TSF function as florigenic substances, and share high sequence similarity with mammalian Raf kinase inhibitor protein (RKIP). Despite their strong similarity to RKIP, the kinase inhibitory activity of FT and TSF remains to be investigated. We performed a yeast two-hybrid screen and found that TSF interacted with FRUCTOKINASE6 (FRK6), which phosphorylates fructose for various metabolic pathways. Among the seven Arabidopsis FRKs, FRK6 and FRK7 have high sequence similarity; therefore, we investigated whether TSF interacts with FRK6 and FRK7. In vitro pull-down assays and bimolecular fluorescence complementation assays revealed that TSF interacts with FRK6 in the nucleus, but not with FRK7. Kinase activity assays suggested that TSF inhibits the kinase activity of FRK6, whereas FT does not. By contrast, neither TSF nor FT inhibits the kinase activity of FRK7. The frk6 and frk7 mutants show slightly delayed flowering, but only under short-day (SD) conditions. Plastochron length is also affected in both frk6 and frk7 mutants under SD conditions. FT expression levels decreased in frk6 mutants, but not in frk7 mutants. Taken together, our findings suggest that TSF physically interacts with FRK6 and affects its kinase activity, whereas FT does not, although these proteins share high sequence similarity.",
keywords = "Arabidopsis, FRK6, Fructokinase, FT, Kinase activity, TSF",
author = "Suhyun Jin and Sunyoung Kim and Ahn, {Ji Hoon}",
year = "2017",
month = "10",
day = "18",
doi = "10.3389/fpls.2017.01807",
language = "English",
volume = "8",
journal = "Frontiers in Plant Science",
issn = "1664-462X",
publisher = "Frontiers Media S. A.",

}

TY - JOUR

T1 - TWIN SISTER of FT (TSF) interacts with FRUCTOKINASE6 and inhibits its kinase activity in arabidopsis

AU - Jin, Suhyun

AU - Kim, Sunyoung

AU - Ahn, Ji Hoon

PY - 2017/10/18

Y1 - 2017/10/18

N2 - In flowering plants, the developmental switch to the reproductive phase is tightly regulated and involves the integration of internal and external signals. FLOWERING LOCUS T (FT) and TWIN SISTER OF FT (TSF) integrate signals from multiple pathways. FT and TSF function as florigenic substances, and share high sequence similarity with mammalian Raf kinase inhibitor protein (RKIP). Despite their strong similarity to RKIP, the kinase inhibitory activity of FT and TSF remains to be investigated. We performed a yeast two-hybrid screen and found that TSF interacted with FRUCTOKINASE6 (FRK6), which phosphorylates fructose for various metabolic pathways. Among the seven Arabidopsis FRKs, FRK6 and FRK7 have high sequence similarity; therefore, we investigated whether TSF interacts with FRK6 and FRK7. In vitro pull-down assays and bimolecular fluorescence complementation assays revealed that TSF interacts with FRK6 in the nucleus, but not with FRK7. Kinase activity assays suggested that TSF inhibits the kinase activity of FRK6, whereas FT does not. By contrast, neither TSF nor FT inhibits the kinase activity of FRK7. The frk6 and frk7 mutants show slightly delayed flowering, but only under short-day (SD) conditions. Plastochron length is also affected in both frk6 and frk7 mutants under SD conditions. FT expression levels decreased in frk6 mutants, but not in frk7 mutants. Taken together, our findings suggest that TSF physically interacts with FRK6 and affects its kinase activity, whereas FT does not, although these proteins share high sequence similarity.

AB - In flowering plants, the developmental switch to the reproductive phase is tightly regulated and involves the integration of internal and external signals. FLOWERING LOCUS T (FT) and TWIN SISTER OF FT (TSF) integrate signals from multiple pathways. FT and TSF function as florigenic substances, and share high sequence similarity with mammalian Raf kinase inhibitor protein (RKIP). Despite their strong similarity to RKIP, the kinase inhibitory activity of FT and TSF remains to be investigated. We performed a yeast two-hybrid screen and found that TSF interacted with FRUCTOKINASE6 (FRK6), which phosphorylates fructose for various metabolic pathways. Among the seven Arabidopsis FRKs, FRK6 and FRK7 have high sequence similarity; therefore, we investigated whether TSF interacts with FRK6 and FRK7. In vitro pull-down assays and bimolecular fluorescence complementation assays revealed that TSF interacts with FRK6 in the nucleus, but not with FRK7. Kinase activity assays suggested that TSF inhibits the kinase activity of FRK6, whereas FT does not. By contrast, neither TSF nor FT inhibits the kinase activity of FRK7. The frk6 and frk7 mutants show slightly delayed flowering, but only under short-day (SD) conditions. Plastochron length is also affected in both frk6 and frk7 mutants under SD conditions. FT expression levels decreased in frk6 mutants, but not in frk7 mutants. Taken together, our findings suggest that TSF physically interacts with FRK6 and affects its kinase activity, whereas FT does not, although these proteins share high sequence similarity.

KW - Arabidopsis

KW - FRK6

KW - Fructokinase

KW - FT

KW - Kinase activity

KW - TSF

UR - http://www.scopus.com/inward/record.url?scp=85034051032&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85034051032&partnerID=8YFLogxK

U2 - 10.3389/fpls.2017.01807

DO - 10.3389/fpls.2017.01807

M3 - Article

VL - 8

JO - Frontiers in Plant Science

JF - Frontiers in Plant Science

SN - 1664-462X

M1 - 1807

ER -