Destabilization of KLF10, a tumor suppressor, relies on thr93 phosphorylation and isomerase association

Yu Chyi Hwang, Chien Hui Yang, Ching Hui Lin, Hui Ju Ch'ang, Vincent H S Chang, Winston C Y Yu

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

KLF10 is now classified as a member of the Krüppel-like transcription factor family and acts as a tumor suppressor. Although KLF10 is originally named as TGF-β-inducible early gene-1 and mimicking the anti-proliferative effect of TGF-β in various carcinoma cells, the transcriptional upregulatory function of KLF10 has been described for a variety of cytokines and in many diseases. Through in vivo and in vitro phosphorylation assays, we identified that KLF10 is a phosphorylated protein in cells. Using yeast-two hybrid screening and site direct mutagenesis, we also identified PIN1 as a novel KLF10 associated protein. PIN1 is a peptidyl-prolyl isomerase enzyme belonging to the parvulin family, which specifically recognizes phosphorylated Ser/Thr-Pro containing substrates. Through protein-protein interaction assays, we showed that the Pro-directed Ser/Thr-Pro motif at Thr-93 in the KLF10 N-terminal region is essential for the interaction between KLF10 and PIN1. More importantly, PIN1 interacts with KLF10 in a phosphorylation-dependent manner and this interaction promotes KLF10 protein degradation in cells. Therefore, KLF10 shows shorter protein stability compared with mutant KLF10 that lacks PIN1 binding ability after cycloheximide treatments. The reversely correlated expression profile between KLF10 and PIN1 as observed in cell lines was also shown in clinic pancreatic cancer specimen. Using in vitro kinase assays and depletion assays, we were able to show that RAF-1 phosphorylates the Thr-93 of KLF10 and affects the KLF10 expression level in cells. Thus these findings as a whole indicate that RAF-1 phosphorylation and PIN1 isomerization together regulate KLF10 stability and further affect the role of KLF10 in tumor progression.

Original languageEnglish
Pages (from-to)3035-3045
Number of pages11
JournalBiochimica et Biophysica Acta - Molecular Cell Research
Volume1833
Issue number12
DOIs
Publication statusPublished - Dec 2013

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Isomerases
Phosphorylation
Neoplasms
Proteins
Peptidylprolyl Isomerase
Protein Stability
Cycloheximide
Pancreatic Neoplasms
Mutagenesis
Proteolysis
Transcription Factors
Phosphotransferases
Yeasts
Cytokines
Carcinoma
Cell Line
Enzymes
Genes
In Vitro Techniques

Keywords

  • KLF10
  • Krüppel-like factor 10
  • PIN1
  • RAF-1
  • TIEG1

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology

Cite this

Destabilization of KLF10, a tumor suppressor, relies on thr93 phosphorylation and isomerase association. / Hwang, Yu Chyi; Yang, Chien Hui; Lin, Ching Hui; Ch'ang, Hui Ju; Chang, Vincent H S; Yu, Winston C Y.

In: Biochimica et Biophysica Acta - Molecular Cell Research, Vol. 1833, No. 12, 12.2013, p. 3035-3045.

Research output: Contribution to journalArticle

Hwang, Yu Chyi ; Yang, Chien Hui ; Lin, Ching Hui ; Ch'ang, Hui Ju ; Chang, Vincent H S ; Yu, Winston C Y. / Destabilization of KLF10, a tumor suppressor, relies on thr93 phosphorylation and isomerase association. In: Biochimica et Biophysica Acta - Molecular Cell Research. 2013 ; Vol. 1833, No. 12. pp. 3035-3045.
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AU - Chang, Vincent H S

AU - Yu, Winston C Y

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KW - KLF10

KW - Krüppel-like factor 10

KW - PIN1

KW - RAF-1

KW - TIEG1

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