Biology subjects

Anielska-Mazur, A.

Publications and source records attributed to Anielska-Mazur, A..

3 recordsLinked to original sources

bioRxiv2025

SnRK2.4 and SnRK2.10 redundantly control developmental leaf senescence by sustaining ABA production and signaling

Plants constantly and precisely control their growth by inducing distinct developmental programs to survive and produce high-quality offspring in the changing environment. The fine-tuning of the development according to endogenous and environmental signals requires exact intercellular signaling and a balanced response. Kinases of the Sucrose non-fermenting-1-Related protein Kinases type 2 (SnRK2s) family primarily take part in the response and adaptation to environmental stress factors. Notably, here we show that two ABA-non-activated SnRK2s, SnRK2.4 and SnRK2.10, are also activated in non-stress conditions in developmentally senescing leaves of Arabidopsis thaliana. Phenotypic, biochemical, and molecular analyses performed on single snrk2.4 or snrk2.10, and double snrk2.4/2.10 kinase mutants showed that SnRK2.4 and SnRK2.10, acting redundantly, promote developmental leaf senescence. Further, SnRK2.4 and SnRK2.10 enhance ABA accumulation in senescing leaves by inducing NCED2, one of key ABA biosynthesis-related genes. The two kinases induce developmental leaf senescence by modulating the expression of multiple ABA-responsive, osmotic stress, and senescence-related genes, such as the senescence master regulators ORE1, ORS1, WRKY33, WRKY75, and ANAC087. Furthermore, we show that SnRK2.4 and SnRK2.10 act upstream of MAPK signaling by enhancing the expression and activity of MAPKKK18, a senescence-inducing kinase. These results document a new regulatory function of SnRK2.4 and SnRK2.10: they are activated in Arabidopsis leaves in response to endogenous signals and redundantly induce developmental leaf senescence by stimulating ABA production and sustaining major ABA-dependent and -independent signaling pathways.

plant biology↗

bioRxiv2024

The Arabidopsis thaliana TRAPPIII subunit AtTRAPPC8/AtTRS85 is involved in ER functioning and autophagy

TRAPP (transport protein particle) tethering complexes are known for their function as Rab-GTPase exchange factors (GEFs). Two versions of the complex are considered functionally separate: TRAPPII, an activator of GTPases of the Rab11 family (RabA in plants) which functions in post-Golgi sorting, and TRAPPIII, activating the Rab1 family (RabD in plants) which regulates ER-to-Golgi trafficking and autophagy. In Arabidopsis thaliana, the TRAPPIII complex has been identified and its subunit composition established, but little is known about its functions. Here, we found that binary subunit interactions of the plant TRAPPIII complex are analogous to those of metazoan TRAPPIII, with the two large subunits TRAPPC8 and -C11 linking the TRAPP core and the small C12-C13 dimer. To gain insight into the functions of TRAPPIII in plants, we characterized two A. thaliana trappc8 mutants. The mutants display abnormalities in plant morphology, in particular in flower and seed development. They also have autophagic defects, constitutive ER stress response, and elevated levels of the ER lipid dolichol - an indispensable cofactor of protein glycosylation. These results show that plant TRAPPC8 is involved in multiple trafficking steps in the cells and they suggest a novel link between ER membrane turnover and dolichol levels. HIGHLIGHTArabidopsis thaliana TRAPPC8 is necessary for correct functioning of the ER, in particular for its lipid homeostasis. Dysruption of TRAPPC8 leads to defects in secretion, autophagosome formation, and plant development.

plant biology↗

bioRxiv2023

Phosphorylation Promotes Liquid-Liquid Phase Separation of GRP8 and Its Assembly into Stress Granules Upon Salinity Stress in Arabidopsis

Drought and salinity are major environmental stresses affecting plant development and growth. SNF1-related protein kinases type 2 (SnRK2s) are key regulators of the plant responses to water deficit and salt stress. Here, we show that Arabidopsis thaliana Glycine-Rich RNA-Binding Protein 8 (GRP8) is a target of abscisic acid (ABA)-non-activated SnRK2s and negatively regulates root growth and seed germination under salt stress. In response to salinity, GRP8 assembles into stress granules (SGs). We show that in addition to the GRP8 C-terminal glycine-rich intrinsically disordered region (IRD), the N-terminal RNA recognition motif (RRM) plays a key role in this process. Phosphorylation of S27 in the RRM by SnRK2s significantly affects the structural dynamics of GRP8, facilitates its dimerization and subsequent liquid-liquid phase separation. Thus, we show that in addition to the known role of IDRs in recruitment into SGs, the RRM plays a decisive role.

plant biology↗