Biology subjects

Aniento, F.

Publications and source records attributed to Aniento, F..

2 recordsLinked to original sources

bioRxiv2026

SEC16A/MAG5-mediated ER export shapes ABA receptor homeostasis

The phytohormone abscisic acid (ABA) controls plant adaptation to environmental stress through PYR/PYL/RCAR receptors. Regulated receptor turnover through ubiquitination and endosomal trafficking, including ESCRT-dependent vacuolar degradation, is a major mechanism controlling ABA signalling. However, whether ABA receptor homeostasis is established during the early secretory pathway remains unknown. Using complementary cell biological and biochemical approaches, we define a constitutive early secretory pool of the ABA receptors PYR1 and PYL4 associated with the endoplasmic reticulum (ER) and the Golgi apparatus (GA). Genetic, cell biological and pharmacological analyses reveal that the COPII scaffold protein SEC16A (also known as MAG5) is required for the proper trafficking and homeostasis of this receptor pool. Loss of MAG5 causes intracellular receptor accumulation, impaired trafficking towards late endosomal compartments and enhanced ABA signalling without affecting endogenous ABA accumulation. Together, our findings establish the early secretory pathway as an integral component of the ABA signalling network and demonstrate that MAG5-mediated ER export shapes ABA receptor homeostasis by coordinating receptor trafficking throughout the endomembrane system, revealing the ER as a key regulatory compartment for ABA receptor homeostasis.

plant biology↗

bioRxiv2021

Function of AtPGAP1 in GPI anchor lipid remodeling and transport to the cell surface of GPI-anchored proteins

GPI-anchored proteins (GPI-APs) play an important role in a variety of plant biological processes including growth, stress response, morphogenesis, signalling and cell wall biosynthesis. The GPI-anchor contains a lipid-linked glycan backbone that is synthesized in the endoplasmic reticulum (ER) where it is subsequently transferred to the C-terminus of proteins containing a GPI signal peptide by a GPI transamidase. Once the GPI anchor is attached to the protein, the glycan and lipid moieties are remodelled. In mammals and yeast, this remodelling is required for GPI-APs to be included in Coat Protein II (COPII) coated vesicles for their ER export and subsequent transport to the cell surface. The first reaction of lipid remodelling is the removal of the acyl chain from the inositol group by Bst1p (yeast) and PGAP1 (mammals). In this work, we have used a loss-of-function approach to study the role of PGAP1/Bst1 like genes in plants. We have found that Arabidopsis PGAP1 localizes to the ER and probably functions as the GPI inositol-deacylase which cleaves the acyl chain from the inositol ring of the GPI anchor. In addition, we show that PGAP1 function is required for efficient ER export and transport to the cell surface of GPI-APs. One sentence summaryGPI anchor lipid remodeling in GPI-anchored proteins is required for their transport to the cell surface in Arabidopsis.

cell biology↗