Protein kinase C modulates light responses in Neurospora by regulating the blue light photoreceptor WC-1.
The Neurospora protein kinase C (NPKC) is a regulator of light responsive genes. We have studied the function of NPKC in light response by investigating its biochemical and functional interaction with the blue light photoreceptor white-collar 1 (WC-1), showing that activation of NPKC leads to a significant decrease in WC-1 protein levels. Furthermore, we show that WC-1 and NPKC interact in a light-regulated manner in vivo, and that protein kinase C (PKC) phosphorylates WC-1 in vitro. We designed dominant negative and constitutively active forms of PKC which are able to induce either a large increase of WC-1 protein level or a strong reduction respectively. Moreover, these changes in PKC activity result in an altered light response. As WC-1 is a key component of Neurospora circadian clock and regulates the clock oscillator component FRQ we investigated the effect of NPKC-mutated forms on FRQ levels. We show that changes in PKC activity affect FRQ levels and the robustness of the circadian clock. Together these data identify NPKC as a novel component of the Neurospora light signal transduction pathway that modulates the circadian clock.
Franchi
Lisa
L
Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biotecnologie Cellulari ed Ematologia, Sezione di Genetica Molecolare, Università di Roma La Sapienza, Policlinico Umberto I, Viale Regina Elena 324, 00161 Roma, Italy.
Fulci
Valerio
V
Macino
Giuseppe
G
D002940:Circadian Rhythm / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D008027:Light; D009491:Neurospora / Q000502:physiology*; D011493:Protein Kinase C / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D014157:Transcription Factors; C105589:wc-1 protein, Neurospora crassa; C103772:white collar 2 protein, Neurospora; D011493:Protein Kinase C