Haiyan Jia

Biography

Research directions:

1. Determine the molecular mechanisms underlying the G-protein role in balancing disease resistance and yield for application to crop improvement programs.

An optimized balance between growth and immunity requires G-protein signaling. As molecular switches, heterotrimeric G protein complexes link extracellular signals perceived by G protein–coupled receptors (GPCRs) to downstream effectors in regulating cellular responses. The G protein complex is composed of a Gα subunit that binds GDP and GTP and a Gβγ dimer. The complex undergoes a cycle of activation by GTP binding and deactivation by GTP hydrolysis. In Arabidopsis thaliana, the Gα subunit is kept in its basal state by a 7-transmembrane GPCR like receptor RGS1 (regulator of G protein signaling 1).

I have developed a combination of genetic, biochemical, and biotechnological tools, along with a network of active collaborators within UNC and beyond.

Results thus far provide key insights including:
1) A specific set of signals and phosphorylation-dependent G protein activations regulate plant resistance to a broad spectrum of plant pathogens;
2) G proteins are negative regulators of plant jasmonic acid (JA) signaling;
3) The bacterial effector, HopBB1, targets Gβ, TCP14 and JAZ3 for SCF(COI1) proteasomal degradation, thus activating JA response genes and promoting bacterial virulence;
4) Gα enhances the stability of Gβ, TCP14 and JAZ3 by blocking JA- and HopBB1-triggered SCF(COI1) degradation in the proteasome;
5) This stability is regulated by interactions with sugar signaling through the RGS1-SUS (sucrose synthase) complex, which in turn modulates G protein signaling and thus the plant immunity-growth balance; and
6) Genetic engineering of the G-protein signaling pathway enhances plant disease resistance to a broad spectrum of pathogens.

Related publications:
(The link: https://scholar.google.com/citations?user=GuOF45YAAAAJ&hl=en)

Jia H, Jorda L, Valentin NH, He SY, Tropsha A, Molina A, Dangl J and Jones AM (2024). A G-Protein Coupled TCP14-JAZ3 Circuit Mediates Broad Disease Resistance by Repressing JA Signaling. (Molecular plant, in review).

Jia H, Watkins J, Lou F, Jones AM (2024). A Novel Apoplastic Sugar Complex Sucrose Synthase and RGS1 in plant growth and defense. (In preparation).

Watkins, J.M., Ross-Elliott, T.J., Shan, X., Lou, F., Dreyer, B., Tunc-Ozdemir, M., Jia, H. et al. (2021) Differential regulation of G protein signaling in Arabidopsis through two distinct pathways that internalize AtRGS1. Science Signaling. https://www.science.org/doi/10.1126/scisignal.abe4090

Jia H, Song G, Werth EG, Walley JW, Hicks LM, and Jones AM (2019) Receptor-Like Kinase Phosphorylation of Arabidopsis Heterotrimeric G-Protein Gα-Subunit AtGPA1. Proteomics. https://doi.org/10.1002/pmic.201900265. (Cover Article)

Lou F, Abramyan TM, Jia H, Tropsha A, Jones AM. (2019) An atypical heterotrimeric Gα protein has substantially reduced nucleotide binding but retains nucleotide-independent interactions with its cognate RGS protein and Gβγ dimer. JBSD. https://doi.org/10.1080/07391102.2019.1704879.

Li B, Tunc-Ozdemir M, Urano D, Jia H, Werth EG, Mowrey DD, Hicks LM, Dokholyan NV, Torres MP, Jones AM (2018) Tyrosine phosphorylation switching of a G protein substrate. J Biol Chem. https://doi.org/10.1074/jbc.RA117.000163

2. Studied the molecular functional evolution of RNA interference pathways in animals and in plants through combination of phylogenetic analyses, modeling of protein structures, CRISPR gene editing and RNA sequencing analysis.

Related Publications:
Jia H, Aadland K, Kolaczkowski O, Kolaczkowski B (2021). Direct molecular evidence for an ancient, conserved developmental toolkit controlling post-transcriptional gene regulation in land plants. Mol Biol Evol: https://doi.org/10.1093/molbev/msab201

Jia H, Kolaczkowski O, Rolland J, Kolaczkowski B (2017) Increased affinity for RNA targets evolved early in animal and plant Dicer lineages through different structural mechanisms. Mol Biol Evol: DOI: https://doi.org/10.1093/molbev/msx187

3. Demonstrated the distinct functions of the LAFL(LEC1/ABI3/FUS3/LEC2) and VAL B3-domain transcription factors and their B3 domains in regulating seed development and seed germination.

Related Publications:

Jia H, Suzuki M, McCarty DR (2021) Structural variation affecting DNA backbone interactions underlies adaptation of B3 DNA binding domains to constraints imposed by protein architecture. Nucleic Acids Research. https://doi.org/10.1093/nar/gkab257

Jia H, Suzuki M, McCarty DR (2014) Regulation of the seed to seedling developmental phase transition by the LAFL and VAL transcription factor networks. WIREs Dev Biol: https://doi.org/10.1002/wdev.126

Jia H, McCarty DR, Suzuki M (2013) Distinct roles of LAFL network genes in promoting the embryonic seedling fate in the absence of VAL repression. Plant Physiol: DOI: https://doi.org/10.1104/pp.113.220988