Fig. 5

Model showing curtovirus C4 regulated BR-signaling pathway dependent (BRSP-dependent) and BRSP-independent functions at 12-hpi. In the absence of BR, BES1 and BZR1 are phosphorylated by AtSKs, inactivating the transcription factors. In the presence of BR or the BCTV C4 protein, the AtSKs are inactivated, which results in the dephosphorylation and activation of BES1 and BZR1. Activated BES1 and BZR1 locate to the nucleus and control expression of BR-biosynthetic genes and BR-responsive genes. Under constant C4 presence, the result is the disruption of hormone homeostasis. C4 also regulates expression of genes not directly regulated by the BR-signaling pathway (BRSP-independent), having early effects on regulatory pathways affecting cellular processes indicated in blue. The image in this figure was generated by the corresponding author