Membrane trafficking and receptor-kinase signaling events modulate cell adhesion in Arabidopsis Public Deposited

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  • March 21, 2019
  • Leslie, Michelle Erin
    • Affiliation: School of Medicine, Curriculum in Genetics and Molecular Biology
  • Plants shed entire organs to facilitate remodeling of their architecture and reproductive success. Organ shedding, or abscission, is a highly specialized process that involves the differentiation of abscission zones (AZs) wherein given the proper cues, cell separation is activated. In a screen for mutations that block the shedding of Arabidopsis floral organs, an ADP-ribosylation factor-GTPase-activating protein (ARF-GAP) was identified and named NEVERSHED (NEV). Using a NEV-specific antibody and a set of plant endomembrane markers, I found that NEV localizes to the trans-Golgi network and putative recycling endosome. Interestingly, mutations in NEV cause defects in the structure of the Golgi apparatus and extensive accumulation of vesicles adjacent to the AZ cell walls. Through a secondary screen for mutations that restore organ shedding in nev flowers, I identified a leucine-rich repeat receptor-like kinase (LRR-RLK), EVERSHED (EVR), that functions as an inhibitor of abscission. EVR belongs to LRR-RLK subfamily XI, which also includes the HAESA and HAESA-LIKE2 RLKs that are redundantly required for abscission. Defects in the Golgi structure in nev AZ cells are rescued by a mutation in EVR, suggesting that like NEV, EVR may regulate membrane trafficking during abscission. In addition to EVR, we identified the SERK1 LRR-RLK and CAST AWAY receptor-like cytoplasmic kinase as inhibitors of abscission through suppressor analysis of nev. Using the bimolecular fluorescence complementation assay in Arabidopsis leaf protoplasts, we have detected interactions between EVR, CAST AWAY and HAESA. I present here a working model that integrates the roles of membrane trafficking and cell signaling during the abscission process.
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  • "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Curriculum in Genetics and Molecular Biology."
  • Liljegren, Sarah J.
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  • Chapel Hill, NC
  • Open access

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