Membrane binding of disordered plant dehydrins is tuned by phosphorylation and coordination of Ca2+ and Zn2+ ions.
(English)Manuscript (preprint) (Other academic)
Dehydrins are intrinsically disordered proteins expressed under water- related stress in plants. As a clue to their function, some dehydrins are found to interact in an orderly manner with negatively-charged lipids, supporting the idea of a key role in safeguarding membrane integrity. We have earlier reported that this lipid interaction is modulated electrostatically. Of particular interest is the pronounced effect of local charge that shed light on how dehydrin function is regulated in vivo. In this study we test the generality of this proposition on four dehydrins from Arabidopsis thaliana representing different dehydrin subgroups. The results show that membrane interaction of dehydrins in their apo state is correlated to their protein net charge. Also, we explore further putative regulation mechanism by investigating the additive role of ion coordination and phosphorylation on membrane binding. The results show that coordination of Ca2+ and Zn2+ have markedly different effects. Coordination of Ca2+ augments mainly the membrane affinity of dehydrins that already bind lipids in their apo states (Lti30 and Rab18). Coordination of Zn2+, on the other hand, induces membrane binding and vesicle assembly of all tested proteins, also those that fail to bind membranes in the absence of metal ions (Cor47 or Lti29). Finally, we observe that the effect of Ca2+ is effectively enhanced by phosphorylation. The observations corroborate the idea of a sensitive and multifaceted regulatory mechanism of the dehydrin function in stressed plant cells but point also at a functional diversity.
Dehydrin, intrinsically disordered proteins, Lea-proteins, membrane binding, calcium, zinc, phosphorylation
Biochemistry and Molecular Biology
Research subject Biochemistry
IdentifiersURN: urn:nbn:se:su:diva-136023OAI: oai:DiVA.org:su-136023DiVA: diva2:1050496