The Role of G Proteins in the Polarity of Drosophila Neurons

Open Access
Author:
Jones, Evan Anthony
Area of Honors:
Biochemistry and Molecular Biology
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Melissa Rolls, Thesis Supervisor
  • Ming Tien, Honors Advisor
  • Scott Brian Selleck, Faculty Reader
Keywords:
  • G Protein
  • Microtubule Polarity
  • Neuron
  • ddaE
  • GPCR
  • Adenylate Cyclase
  • Dendrite
  • Neurodegenerative Disease
Abstract:
It is well-established that axons and dendrites are specified to have different functions in the neuron, but the origin of this specification is still largely unknown. Microtubules play a vital role in the transportation of cellular components in these structures, and behave differentially between axons and dendrites. Microtubules create polarized tracks in the cell, and a more-developed understanding of the mechanism controlling microtubule polarity may give insight into various neurodegenerative diseases. It has been shown that certain cellular components are involved in the maintenance of microtubule polarity, such a component is adenomatous polyposis coli 2 (APC2). From the foundational knowledge that already exists on microtubule polarity, an experimental course was designed to examine the role of guanine nucleotide binding proteins (G proteins) in the mechanism of polarity control. Through RNAi knockdown and fluorescent microscopy experiments a G protein subunit, Gsα, was found to be a vital component in maintaining microtubule polarity in the dendrite. From this initial discovery, a broader picture of the mechanism was elucidated through further experimentation. RNAi knockdowns of a G protein coupled receptor (GPCR), Fz, and an adenylate cyclase, Rut, were found to also disrupt microtubule polarity in the dendrite. These findings suggest that Fz signals through Gsα and that Gsα signals through Rut. This signaling module used in learning and memory also seems to play a role in controlling microtubule organization.