394 / 2019-02-20 10:30:10

A Novel Crosstalk between Endomemtrane Trafficking and ABA Singaling

ABA,phosphorylation,FREE1,Endomembrane trafficking

全体主题 > Cell Biology

The endosomal sorting complex required for transport (ESCRT) machinery has been well documented for its function in endosomal sorting in eukaryotes. Here, we demonstrate an up to now unknown and non-endosomal function of the ESCRT component in plants. We show that FYVE domain protein required for endosomal sorting 1 (FREE1), a recently identified plant-specific ESCRT component essential for multivesicular body biogenesis, plays additional functions in the nucleus in transcriptional inhibition of abscisic acid signaling. Upon abscisic acid (ABA) treatment, SnRK2 (SNF1-related protein kinase 2) kinases phosphorylate FREE1, a step requisite for ABA-induced FREE1 nuclear import. In the nucleus, FREE1 interacts with basic leucine zipper transcription factors ABA-RESPONSIVE ELEMENTS BINDING FACTOR4 and ABA-INSENSITIVE5 to reduce their binding to the cis-regulatory sequences of downstream genes. Collectively, our study demonstrates the cross-talk between endomembrane trafficking and ABA signaling at the transcriptional level and highlights the moonlighting properties of plant ESCRT subunit FREE1, which has evolved unique non-endosomal functions in the nucleus besides its roles in membrane trafficking in the cytoplasm. This study has been accepted for publication in Nature Plants, 2019.