Calendar Name: seminars
Scheduled for: Tuesday, April 20 2010, 11:00 - 12:30
Event text: Catherine Perrot-Rechenmann
Institut des Sciences du V�g�tal (ISV), CNRS
Gif sur Yvette
FRANCE
Details: �Cross-talk between ABP1 and TIR1/AFB auxin receptors�
ABSTRACT
The phytohormone auxin is a major regulator of plant
growth and development. Many aspects of these processes
depend on the multiple controls exerted by auxin on
cellular responses as cell expansion and cell division,
and mediated at the molecular level by the regulation of
auxin-responsive genes. Two classes of auxin receptors
have been identified to date: first, the TIR1/AFB F-box
proteins which are part of ubiquitin E3 ligase complexes
and, according to the current auxin signalling model
(reviewed by 1), recruit the AUX/IAA transcriptional
repressors in the presence of auxin to induce their
ubiquitination and degradation by the 26S proteasome;
second, the long-standing and unique auxin binding
protein 1, ABP1, initially identified on its capacity to
bind auxin and demonstrated to induce activation of ion
fluxes at the plasma after auxin binding. Recently, the
detailed characterization of conditional ABP1 knock-down
plants 2,3 revealed that ABP1 is required for almost all
auxin-mediated responses including modulation of gene
expression. In consequence, TIR1/AFB and ABP1 appear to
share the regulation of auxin responsive genes. We have
investigated the relationship between the TIR1/AFBs- and
ABP1-mediated pathways. We have further analyzed the
requirement of ABP1 for auxin mediated gene expression
in roots and developed biochemical and genetic
approaches to analyze its functional interaction with
the SCFTIR1/AFB pathway. Original data leads to a novel
model integrating ABP1 and SCFTIR1/AFBs into a
sophisticated multicomponent auxin signaling pathway,
essential for regulation of auxin responses.
1. Chapman EJ, Estelle M: Annu Rev Genet 2009,
43:265-285.
2. Braun N, Wyrzykowska J, Muller P, David K, Couch D,
Perrot-Rechenmann C, Fleming AJ Plant Cell 2008,
10:2746-2762.
3. Tromas A, Braun N, Muller P, Khodus T, Paponov IA, et
al. PLoS One 2009, 4:e6648.
