The START domain potentiates HD-ZIPIII transcriptional activity

Husbands, Aman Y, Feller, Antje, Aggarwal, Vasudha, Dresden, Courtney E, Holub, Ashton S, Ha, Taekjip, Timmermans, Marja CP (March 2023) The START domain potentiates HD-ZIPIII transcriptional activity. The Plant Cell. ISSN 1040-4651

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Abstract

The CLASS III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIPIII) transcription factors (TFs) were repeatedly deployed over 725 million years of evolution to regulate central developmental innovations. The START domain of this pivotal class of developmental regulators was recognized over twenty years ago, but its putative ligands and functional contributions remain unknown. Here, we demonstrate that the START domain promotes HD-ZIPIII TF homodimerization and increases transcriptional potency. Effects on transcriptional output can be ported onto heterologous TFs, consistent with principles of evolution via domain capture. We also show the START domain binds several species of phospholipids, and that mutations in conserved residues perturbing ligand binding and/or its downstream conformational readout, abolish HD-ZIPIII DNA-binding competence. Our data present a model in which the START domain potentiates transcriptional activity and uses ligand-induced conformational change to render HD-ZIPIII dimers competent to bind DNA. These findings resolve a long-standing mystery in plant development and highlight the flexible and diverse regulatory potential coded within this widely distributed evolutionary module.

Item Type:	Paper
Subjects:	organism description > plant > Arabidopsis bioinformatics bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification bioinformatics > genomics and proteomics > genetics & nucleic acid processing bioinformatics > genomics and proteomics bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > DNA binding protein bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > homeodomain protein bioinformatics > genomics and proteomics > small molecules > cofactors > ligands bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > mutations organism description > plant bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > transcription factor
CSHL Authors:	Husbands, Aman Y. Timmermans, Marja C. P.
SWORD Depositor:	CSHL Elements
Depositing User:	CSHL Elements
Date:	2 March 2023
Date Deposited:	08 Mar 2023 16:14
Last Modified:	10 Jan 2024 19:34
PMCID:	PMC10226595
Related URLs:	Publisher PubMed
URI:	https://repository.cshl.edu/id/eprint/40853

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