Autophagic degradation of the iron transporter IRT1 is mediated by its interaction with the stress-induced TSPO protein in Arabidopsis thaliana
(2022)
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- Arabidopsis thaliana plant acquires iron from the soil through IRON- REGULATED TRANSPORTER 1 (IRT1). Previous work showed that IRT1 is stabilized and mainly localized at the plasma membrane under iron deficiency. The stabilized pool of this metal transporter protein is potentially detrimental to the cell since the level of iron in the cytosol is regulated and toxic mineral such as cadmium or zinc are also substrate of IRT1. In this work we showed that the constitutive expression of a stress-induced translocator protein TSPO reduces IRT1 levels in the plasma membrane. TSPO expression is transiently induced in the root by iron deficiency and is constitutively expressed in the irt1- null mutant. In contrast, overexpression of IRT1 induced TSPO. Pulldown assays and fluorescence microscopy approaches revealed that TSPO established physical interactions with IRT1 in theArabidopsisroot cells and the resulting complex is degraded through autophagy. Interestingly, constitutive expression of TSPO, and treatment resulting in transient TSPO expression such as abscisic acid treatment, salinity, osmotic stress, or pharmacological treatments inducing autophagy in the root cells resulted in IRT1 degradation. TSPO expression triggered IRT1 localization in vesicular structures reminiscent of autophagosomes. These data support a role for TSPO in IRT1 downregulation under multi-stress conditions, and specifically under iron deficiency conditions.
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Ayeb, H. (2022). Autophagic degradation of the iron transporter IRT1 is mediated by its interaction with the stress-induced TSPO protein in Arabidopsis thaliana. https://hdl.handle.net/2078.5/24976