Characterization of a novel zinc chaperone in arabidopsis

Authors: ZHANG, LIFANG - Cold Spring Harbor Laboratory; HU, FENGLE - Cold Spring Harbor Laboratory; PASQUINI, MIRIAM - Brookhaven National Laboratory; XIE, MENG - Brookhaven National Laboratory; BLABY-HASS, CRYSTEN - Brookhaven National Laboratory; Ware, Doreen

Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 6/2/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Zinc is a vital micronutrient for plants. It is a constituent of approximately 2400 Arabidopsis proteins and an essential cofactor of enzymes and many regulatory proteins [1]. However, how zinc-dependent proteins are loaded with zinc was previously unknown. By leveraging phylogenomic and data-mining analyses combined with an inter-disciplinary experimental approach, we have discovered a novel metal chaperone that delivers zinc to an essential zinc-dependent enzyme during zinc deficiency. We provide evidence that this function is universally conserved from fungi to plants. In plants, we propose that duplication has resulted in analogous zinc-trafficking pathways in the cytosol and chloroplast. In Arabidopsis, there is one zinc chaperone (ZNG1) in the cytoplasm, and two paralogous chaperones (ZNG2A1 and ZNG2A2) localized to chloroplast. We have obtained and characterized corresponding mutants for ZNG1, ZNG2A1, ZNG2A2, MAPs (the target zinc-dependent proteins) and made several crosses among these mutants. Here we present preliminary data of the characterization of plant ZNG1.Using Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFc) studies, we show that ZNG1 can interact with the cytosolic target, methionine aminopeptidase, MAP1A, as we have found in yeast. Our hypothesis is that Plant ZNG1 is an activator of cytosolic MAP1, and cytosolic MAP2 can function as a back-up enzyme when cytosolic MAP1 activity is compromised.