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Reversion of the Arabidopsis UV-B photoreceptor UVR8 to the homodimeric ground state.

ABSTRACT: Plants require the UV-B photoreceptor UV resistance locus 8 (UVR8) for acclimation and survival in sunlight. Upon UV-B perception, UVR8 switches instantaneously from a homodimeric to monomeric configuration, which leads to interaction with the key signaling protein constitutively photomorphogenic 1 (COP1) and induction of UV-B-protective responses. Here, we show that UVR8 monomerization is reversible in vivo, restoring the homodimeric ground state. We also demonstrate that the UVR8-interacting proteins repressor of UV-B photomorphogenesis (RUP)1 and RUP2 mediate UVR8 redimerization independently of COP1. UVR8 redimerization consequently disrupts the UVR8-COP1 interaction, which halts signaling. Our results identify a key role of RUP1- and RUP2-mediated UVR8 redimerization in photoreceptor inactivation, a crucial process that regenerates reactivatable UVR8 homodimers.

SUBMITTER: Heijde M

PROVIDER: S-EPMC3549095 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature

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Reversion of the Arabidopsis UV-B photoreceptor UVR8 to the homodimeric ground state.

Heijde Marc M Ulm Roman R

Proceedings of the National Academy of Sciences of the United States of America 20121231 3

Plants require the UV-B photoreceptor UV resistance locus 8 (UVR8) for acclimation and survival in sunlight. Upon UV-B perception, UVR8 switches instantaneously from a homodimeric to monomeric configuration, which leads to interaction with the key signaling protein constitutively photomorphogenic 1 (COP1) and induction of UV-B-protective responses. Here, we show that UVR8 monomerization is reversible in vivo, restoring the homodimeric ground state. We also demonstrate that the UVR8-interacting p ...[more]

PMID: 23277547

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