TY  - GEN
T1  - Arabidopsis thaliana growth is independently controlled by the SUMO E3 ligase SIZ1 and Hexokinase 1
AU  - Castro, Pedro Humberto
AU  - Verde, Nuno
AU  - Azevedo, Herlander
DO  - 10.17912/micropub.biology.000270
UR  - http://beta.micropublication.org/journals/biology/micropub-biology-000270/
AB  - Carbohydrate metabolism needs to be tightly regulated in order to ensure an organism’s survival. For this reason, several sensing mechanisms are in permanent alert to monitor and maintain homeostatic levels of sugars (Li and Sheen, 2016). For instance, glucose cellular levels can be sensed by different signaling proteins, including the Hexokinase 1 (HXK1), a moonlighting protein with both metabolic (glucose phosphorylation) and sensing/transduction functions (Moore et al., 2003). In a situation of excess glucose, HXK1 forms a nuclear complex that directly inhibits photosynthesis-related genes, reducing the synthesis of more glucose (Cho et al., 2006). Interestingly, HXK1 loss-of-function mutants lose the capacity to sense external sugar and, consequently, are capable of germinating in high percentages of external sugar supplementation. Indeed, the reference HXK1 mutant gin2-1, that harbors a nonsense mutation (Q432*) in Arabidopsis thaliana ecotype Landsberg erecta (Ler), was obtained from a forward screening for glucose insensitive (gin) mutants that do not suffer post-germinative growth arrest (PGGA) on a 6% glucose MS medium (Moore et al., 2003). Broadly, a myriad of phenotypic defects have been described for HXK1 mutants, highlighting the protein’s importance in the regulation of plant development (Aguilera-Alvarado and Sanchez-Nieto, 2017; Van Dingenen et al., 2019). Considering HXK1’s importance to plant fitness and development, one expects its activity to be tightly controlled.
PY  - 2020
JO  - microPublication Biology
ER  -