Groucho suppresses Pax2 transactivation byinhibition of JNK-mediated phosphorylation

The EMBO Journal Vol. 22 No. 20 pp. 5522-5529, 2003

Groucho -wnt/b-cat

-human Groucho family: TLE-1/2/3/4 (transducin-like enhancer of split) hAES(amino-termianl enhancer of split)

-mouse Groucho family: Grg-1/2/3/4 & Grg-5

Q domain: glutamine rich

GP domain: glycine/proline rich

CcN domain

SP domain:serine/proline rich

Four WD40 repeats domain

tetramerization(leucine zipper-like structure)binding to n-terminal of H3Interaction with HDAC

Putative casein kinase II/cdc2 phosphorylation sitesnuclear localization signal

protein interaction

Pax: paired box gene-pax 1~9, DNA binding transcription factor-activation and repression of downstream target genes-regulators of organogenesis & key factors in maintaining pluripotency of

stem cell populations during development-Mutations of the Pax: profound developmental defects in organisms as

diverse as flies, mice and humans.

PD domain: bipartite paired domain N- & C-terminal subdomains three α-helices third helix of each subdomain (red) contact with the major groove of DNA

OP motif: octapeptide motif HD domain: homeodomain helix–turn–helix structure.

TD domain: C-term transactivation domain

Pax2/5/8-the Pax2/5/8 proteins contain a conserved octapeptide with homology to

the engrailed-type repressor sequence.

OP domain

Engrailed homology region of the homeodomain transcription factors EN2 and Goosecoid(GSC)

-pax 2/5/8 contains partial homeodomain(HD1) that consistutes an interation surface for both the retinoblastoma(Rb) gene product and the TATA-binding protein (Eberhard and busslinger,1999)

- The ability of Pax2 to activate transcription is enhanced by phosphorylation of its activation domain by the JNK (Cai et al., 2002)

Pax2-JNK-groucho

- Pax5 transactivation activity can also be negatively regulated through interactions with the Groucho/TLE family of co-repressors (Eberhard et al.,2000)

-In mouse and man, the Pax2 gene is essential for the developmentof the kidneys, optic cup, and inner ear.

-SFRP2 gene is a target of the Pax2 transcription factor (J Biol Chem.2003 )

Fig1. Grg4 physically interacts with Pax2

TSA(trichostatin A): HDAC inhibitor

Fig. 2. Grg4 inhibits the JNK enhanced transactivation potential of Pax2.

Gal4 DNA binding element luciGal 4 DNA binding domain

Activation domain Elk or c-Jun

Fig. 3. Grg4 inhibits phosphorylation of Pax2 in a DNA-dependent manner

In vivo phospho-labeling of 293 cells

Fig. 4. Co-expression of Pax2 and Grg4 in the embryonic kidney and neural tube.

E-cadherin (green)

anti-Pax2 (red) anti-Grg4 (red)

E15.5 embryos. immunostaining

Kidney

Spinalcord

s-shaped body (arrow).renal vesicles (arrowhead)

embryonic pancreas

E16 tissue/ NE