Graduate Students Highlights

Awards

Bethanie-Michelle Statler Minorities Affairs Committee Travel Award, honorable mention at The Predoctoral Ford Foundation Fellowship (2018)
Todd Widhelm UIC Travel Award (2018)
Elsa Anderson Fulbright Student Research Fellowship (2018)
Yuliana Rowe Graduate Teaching Award (Fall 2017)

Publications

Todd Widhelm

Oligocene origin and drivers of diversification in the genus Sticta (Lobariaceae, Ascomycota). Molecular Phylogenetics and Evolution 126, 58–73 (2018).

Article 

Todd Widhelm

Outreach & Service

Xin Wang Discovery Squad - Field Museum
Bethanie-Michelle Statler Chicago Area Undergraduate Research Symposium, Louis Stokes Midwest Center of Excellence Conference, LSAMP, Expanding Your Horizons Chicago, ACT-SO, Graduate Student Council
Chih-Yu Pai Graduate Women in Science (GWIS) - Chicago chapter

Presentations

Bethanie-Michelle Statler

ASCB-EMBO conference, San Diego

Date: December 8-12, 2018

Title: Redistribution of the yeast pheromone receptor during gradient sensing requires the RGS protein Sst2

Chemotropism, or directed cell growth, depends on the ability of cells to accurately sense chemical gradients. During mating, the budding yeast Saccharomyces cerevisiae uses GPCRs to sense the pheromone secreted by potential mating partners. In response, yeast cells form a mating projection in the direction of the nearest partner. The GPCR Ste2 is distributed uniformly on the membrane in vegetative cells. Until recently, it was thought that the receptor and G protein polarize directly to the chemotropic site (CS), in the direction of the pheromone source. On the contrary, we have discovered that mating cells first polarize the receptor and G protein to an intrinsic default polarity site (DS) before redistributing these signaling proteins to the CS. We refer to this redistribution as tracking. This finding led us to divide chemotropism into three stages: polarity establishment at the DS, tracking from the DS to the CS, and stabilization at the CS just prior to morphogenesis. Sst2 is an RGS (regulator of G protein signaling) family member that stimulates the GTPase activity of Gα-GTP and preferentially binds to unphosphorylated receptor. Sst2 is critical for gradient sensing and has been proposed to act as a signaling barrier surrounding the mating projection. It is currently unknown where Sst2 localizes and when it is active during polarity establishment, redistribution, and morphogenesis. We used time-lapse fluorescent imaging to follow the dynamic localization of Sst2-GFP and Ste2-GFP in mating yeast cells. Sst2 appeared at the DS after the receptor, started tracking just before the receptor, and tracked from the DS to the CS like the receptor. Upon morphogenesis, Sst2 surrounded the stabilized receptor at the mating projection. Sst2 localization is likely determined by active-unphosphorylated receptor and the availability of its substrate, Gα-GTP. This distribution is consistent with Sst2 serving as a signaling barrier. Notably, the receptor failed to redistribute in sst2∆ cells, suggesting that the spatiotemporal dynamics of Sst2-catalyzed G-protein recycling is critical to gradient sensing.

 

Chih-Yu Pai

Midwest Yeast Meeting, Northwestern University

Date: November 10, 2018 

Title: The yeast claudin Dcv1 contributes to the polarization of mating functions

 

Dina Beeler-Muscat

PhD Dissertation, Science and Engineering Labs – East 4289

Date: October 19, 2018

Title: Characterization of Optimus Prime, A Novel Regulator of Synaptic Transmission

 

Xin Wang

Yeast Genetics Meeting, Stanford University, California

Date: August 22-26, 2018

Title: Mating yeast cells become competent to sense pheromone gradients by assembling signaling and trafficking proteins at the default polarity site

 

Chih-Yu Pai

Yeast Genetics Meeting, Stanford University, California

Date: August 22-26, 2018 

Title: The yeast claudin Dcv1 contributes to the polarization of mating functions

 

Michael Ricketts

Invited Speaker- Microbiome Soil Sensors Workshop in La Jolla, CA

Date: August 21-22

Title: Challenges in microbial community analysis specific to Arctic soils

 

Todd Widhelm

American Bryological and Lichenological Society’s annual conference, Rocky Mountain Field Station

Date: July 14, 2018

Title: Assessing evolutionary relationships in Lobariaceae using target capture