GIGANTEA is a co-chaperone which facilitates maturation of ZEITLUPE in the Arabidopsis circadian clock

Abstract

Circadian clock systems help establish the correct daily phasing of the behavioral, developmental, and molecular events needed for the proper coordination of physiology and metabolism. The circadian oscillator comprises transcription–translation feedback loops but also requires post-translational processes that regulate clock protein homeostasis. GIGANTEA is a unique plant protein involved in the maintenance and control of numerous facets of plant physiology and development. Through an unknown mechanism GIGANTEA stabilizes the F-box protein ZEITLUPE, a key regulator of the circadian clock. Here, we show that GIGANTEA has general protein chaperone activity and can act to specifically facilitate ZEITLUPE maturation into an active form in vitro and in planta. GIGANTEA forms a ternary complex with HSP90 and ZEITLUPE and its co-chaperone action synergistically enhances HSP90/HSP70 maturation of ZEITLUPE in vitro. These results identify a molecular mechanism for GIGANTEA activity that can explain its wide-ranging role in plant biology.

Long-lived polarization memory in the electronic states of lead-halide perovskites from local structural dynamics

“…No significant variation in these decay times is found for other probe energies, which suggests that the loss of the photoexcited anisotropy occurs through a common process for all states. These timescales are much longer than typical phonon emission 34 – 36 and carrier cooling times 5 , 30 , 37 , but are in agreement with reported timescales for dynamic fluctuations of the crystal lattice 8 , 38 . We take these observations as an indication that the origin for the persistent polarization anisotropy relates to the crystal conformation, rather than a particular carrier-phonon interaction.…”

Long-lived polarization memory in the electronic states of lead-halide perovskites from local structural dynamics

“…No significant variation in these decay times is found for other probe energies, which suggests that the loss of the photoexcited anisotropy occurs through a common process for all states. These timescales are much longer than typical phonon emission 34 – 36 and carrier cooling times 5 , 30 , 37 , but are in agreement with reported timescales for dynamic fluctuations of the crystal lattice 8 , 38 . We take these observations as an indication that the origin for the persistent polarization anisotropy relates to the crystal conformation, rather than a particular carrier-phonon interaction.…”

Compensatory Mutations in GI and ZTL May Modulate Temperature Compensation in the Circadian Clock

“…4). This finding is consistent with the role of GI in the maturation of functional ZTL (Kim et al, 2007;Cha et al, 2017).…”

Functional domain studies uncover novel roles for the ZTL Kelch repeat domain in clock function

“…Odds Score > 3), while the interactions with HSP90.4 and 90.5 were not statistically significant. The identification of a statistically significant interaction between the ZTL Kelch domain and HSP90 suggests that ZTL may be able to interact directly with HSP90 in the absence of GI, in addition to the ZTL-GI-HSP90 tri-partite complex that had been previously suggested [27,40]. However, lack of any peptides from other published ZTL interactors in our IP/MS results suggests that, consistent with previously published results [13,[29][30][31] and interacting partners of ZTL.…”

Long-lived polarization memory in the electronic states of lead-halide perovskites from local structural dynamics

“…No significant variation in these decay times is found for other probe energies, which suggests that the loss of the photoexcited anisotropy occurs through a common process for all states. These timescales are much longer than typical phonon emission 34 – 36 and carrier cooling times 5 , 30 , 37 , but are in agreement with reported timescales for dynamic fluctuations of the crystal lattice 8 , 38 . We take these observations as an indication that the origin for the persistent polarization anisotropy relates to the crystal conformation, rather than a particular carrier-phonon interaction.…”

Compensatory Mutations in GI and ZTL May Modulate Temperature Compensation in the Circadian Clock

“…4). This finding is consistent with the role of GI in the maturation of functional ZTL (Kim et al, 2007;Cha et al, 2017).…”

Functional domain studies uncover novel roles for the ZTL Kelch repeat domain in clock function

“…Odds Score > 3), while the interactions with HSP90.4 and 90.5 were not statistically significant. The identification of a statistically significant interaction between the ZTL Kelch domain and HSP90 suggests that ZTL may be able to interact directly with HSP90 in the absence of GI, in addition to the ZTL-GI-HSP90 tri-partite complex that had been previously suggested [27,40]. However, lack of any peptides from other published ZTL interactors in our IP/MS results suggests that, consistent with previously published results [13,[29][30][31] and interacting partners of ZTL.…”

Long-lived polarization memory in the electronic states of lead-halide perovskites from local structural dynamics

“…No significant variation in these decay times is found for other probe energies, which suggests that the loss of the photoexcited anisotropy occurs through a common process for all states. These timescales are much longer than typical phonon emission 34 – 36 and carrier cooling times 5 , 30 , 37 , but are in agreement with reported timescales for dynamic fluctuations of the crystal lattice 8 , 38 . We take these observations as an indication that the origin for the persistent polarization anisotropy relates to the crystal conformation, rather than a particular carrier-phonon interaction.…”

Compensatory Mutations in GI and ZTL May Modulate Temperature Compensation in the Circadian Clock

“…4). This finding is consistent with the role of GI in the maturation of functional ZTL (Kim et al, 2007;Cha et al, 2017).…”

Functional domain studies uncover novel roles for the ZTL Kelch repeat domain in clock function

“…Odds Score > 3), while the interactions with HSP90.4 and 90.5 were not statistically significant. The identification of a statistically significant interaction between the ZTL Kelch domain and HSP90 suggests that ZTL may be able to interact directly with HSP90 in the absence of GI, in addition to the ZTL-GI-HSP90 tri-partite complex that had been previously suggested [27,40]. However, lack of any peptides from other published ZTL interactors in our IP/MS results suggests that, consistent with previously published results [13,[29][30][31] and interacting partners of ZTL.…”