Interactions between PIAS proteins and SOX9 result in an increase in the cellular concentrations of SOX9

Takako Hattori, Heidi Eberspaecher, Jingfang Lu, Ren Zhang, Tamotsu Nishida, Tomoaki Kahyo, Hideyo Yasuda, Benoit De Crombrugghe

Research output: Contribution to journalArticlepeer-review

55 Citations (Scopus)

Abstract

We have identified PIAS1 (protein inhibitor of activated STAT-1), -3, -xα, and -xβ as SOX9-associated polypeptides using the Gal4-based yeast two-hybrid system and a cDNA library derived from a chondrocytic cell line. These PIAS proteins were shown to interact directly with SOX9 in two-hybrid, co-immunoprecipitation, and electrophoretic mobility shift assays. SOX9 was sumoylated in cotransfection experiments with COS-7 cells using PIAS and SUMO-1 (small ubiquitin-like modifier-1) expression vectors. SOX9 was also sumoylated in vitro by PIAS proteins in the presence of SUMO-1, the SUMO-activating enzyme, and the SUMO-conjugating enzyme. In COS-7 cells, PIAS proteins stimulated the SOX9-dependent transcriptional activity of a Col2a1 promoter-enhancer reporter. This increase in reporter activity was paralleled by an increase in the cellular levels of SOX9. Cotransfection with a SUMO-expressing vector further enhanced the transcriptional activity of this SOX9-dependent Col2a1 reporter in COS-7 cells, and this additional activation was inhibited in the presence of either SUMO-1 mutants or PIAS RING domain mutants or by coexpression of a desumoylation enzyme. Immunofluorescence microscopy of SOX9-transfected COS-7 cells showed that the subnuclear distribution of SOX9 becamemore diffuse in the presence of PIAS1 and SUMO-1. Our results suggest that, by controlling the cellular concentrations of SOX9, PIAS proteins and sumoylation may be part of amajor regulatory system of SOX9 functions.

Original languageEnglish
Pages (from-to)14417-14428
Number of pages12
JournalJournal of Biological Chemistry
Volume281
Issue number20
DOIs
Publication statusPublished - May 19 2006

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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