TY - JOUR
T1 - Functional significance of FRH in regulating the phosphorylation and stability of Neurospora circadian clock protein FRQ
AU - Guo, Jinhu
AU - Cheng, Ping
AU - Liu, Yi
PY - 2010/4/9
Y1 - 2010/4/9
N2 - FREQUENCY (FRQ) is the central component of the Neurospora circadian clock. All FRQ proteins form the FFC complex with FRH (FRQ-interacting RNA helicase) that acts as the negative element in the circadian negative feedback loop by repressing frq mRNA levels. To understand the function of the FRQ-FRH interaction, we mapped and identified the minimal FRQ region that is required for FRQ-FRH interaction. We demonstrated that the FRQ-FRH complex formation is required for the interaction betweenFRQand the White Collar Complex (WCC) and clock function. On the other hand, in the FRQ-FRH complex, FRQ is also required for the FRH-WCC interaction. Disruption of FRQ-FRH interaction or down-regulation of FRH results in hypophosphorylation, rapid degradation of FRQ, as well as low levels of WHITE COLLAR-1 and WHITE COLLAR-2. Furthermore, we showed that the rapid FRQ degradation in the absence of FRH is independent of FWD-1, the ubiquitin E3 ligase of FRQ under normal conditions, thus uncovering an alternative pathway for FRQ degradation.
AB - FREQUENCY (FRQ) is the central component of the Neurospora circadian clock. All FRQ proteins form the FFC complex with FRH (FRQ-interacting RNA helicase) that acts as the negative element in the circadian negative feedback loop by repressing frq mRNA levels. To understand the function of the FRQ-FRH interaction, we mapped and identified the minimal FRQ region that is required for FRQ-FRH interaction. We demonstrated that the FRQ-FRH complex formation is required for the interaction betweenFRQand the White Collar Complex (WCC) and clock function. On the other hand, in the FRQ-FRH complex, FRQ is also required for the FRH-WCC interaction. Disruption of FRQ-FRH interaction or down-regulation of FRH results in hypophosphorylation, rapid degradation of FRQ, as well as low levels of WHITE COLLAR-1 and WHITE COLLAR-2. Furthermore, we showed that the rapid FRQ degradation in the absence of FRH is independent of FWD-1, the ubiquitin E3 ligase of FRQ under normal conditions, thus uncovering an alternative pathway for FRQ degradation.
UR - http://www.scopus.com/inward/record.url?scp=77951228944&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77951228944&partnerID=8YFLogxK
U2 - 10.1074/jbc.M109.071688
DO - 10.1074/jbc.M109.071688
M3 - Article
C2 - 20159972
AN - SCOPUS:77951228944
SN - 0021-9258
VL - 285
SP - 11508
EP - 11515
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 15
ER -