ATG6 project – Nicola Harrison-Lowe
This research project was part of a new initiative focused on understanding the process of autophagy in plants. This inducible process allows for the internal recycling of cellular components in order to prolong an organism’s survival under harsh conditions. The goal of the project was to characterize the role of ATG6 in plant autophagy (homologous to an identified yeast autophagy protein Vps30p) and identify both conserved and novel functions within the plant system. ATG6 has homologues across the eukaryotic spectrum from yeast to humans, where deletion of the human homologue (Beclin1) has been implicated in breast cancer.
Examination of Arabidopsis mutant plants failed to identify any homozygotes, suggesting plants without a functional copy of ATG6 died before developing into seedlings, but why?. Ultimately using a series of biochemical and microscopy techniques, we determined that mutant atg6 pollen (haploid male gametophyte) fails to fertilize eggs, resulting in the loss of homozygotes! See our publication.
Schematic of inducible macroautophagy: In brief an environmental stress related signal (example: low nutrients, lack of sunlight) leads to the induction of autophagy through mTOR and the sequestration of cytosolic components into autophagosomes. These autophagosomes (double membraned lytic vesicles) then dock and fuse with the vacuolar membrane where the contents undergo breakdown. This presumably allows for recycling of cellular components to maintain minimal metabolic processes and prolong organismal survival. (Klionsky and Kim et al, 2000)
Undergraduates and Autophagy
Multiple undergraduates have worked on autophagy related projects, here is a sample of their research topics.
Margaret Du’s project focused on the characterization of the kinase ATG1, an Arabidopsis gene proposed to be involved in autophagy.
Stephanie Gardiner’s project involved the functional analysis of ATG18c, a member of a known gene family whose role is analogous to an autophagy protein in yeast.
Jerry Tomasek’s project involved the putative autophagocytosis protein ATG3 found in Arabidopsis thaliana.
