Kristen Rohli wins 2nd place in Genetics Retreat Poster contest, 2021
Kristen's poster presentation entitled "Hyperglycemia delays ER export of proinsulin via altered ER redox homeostasis" was awarded 2nd place at the Annual Genetics Retreat.
Cierra Boyer passes her comprehensive exam, 2021
Cierra passed her comprehensive exam for the Department of Pharmacology and has moved forward to the next stage of her Ph.D. dissertation work.
"Mitochondrial efflux of citrate and isocitrate is fully dispensable for glucose-stimulated insulin secretion and pancreatic islet β-cell function" selected for cover art in Diabetes, 2021
Images taken for our recent study on the mitochondrial citrate-isocitrate carrier were selected for the cover art of the August edition of Diabetes.
Kristen Rohli receives T32 Fellowship in Genetics, 2021
Kristen’s work has uncovered a novel observation that chronic hyperglycemia associated with Type 2 diabetes results in early defects in the trafficking of the insulin precursor, proinsulin, from the ER to Golgi, leading to impairments in the production of mature insulin. To further study this process, Kristen was awarded a fellowship on the Genetic Program NIH T32 Training Grant.
"Mitochondrial efflux of citrate and isocitrate is fully dispensable for glucose-stimulated insulin secretion and pancreatic islet β-cell function" published in Diabetes, 2021
This study opposes current dogma in the β-cell field by demonstrating that the mitochondrial citrate-isocitrate carrier is not required for glucose-stimulated insulin secretion. Furthermore, we highlight disconnects in our understanding of the roles of Idh1, NADPH, and glutathione in the regulation of β-cell function.
Ashleigh Machado receives ICRU fellowship for 2nd year, 2021
Ashleigh is an undergraduate research assistant in the lab who was once again awarded an Iowa Center for Research by Undergraduates (ICRU) fellowship. She will be examining how Golgi sorting enzymes contribute to insulin granule formation and trafficking during early stages in the development of Type 2 diabetes.
Sandra Blom joins the Stephens lab, 2021
Sandra joins the Stephens lab from the Molecular Medicine graduate program for her Ph.D. training.
Kristen Rohli's digital poster is on display, 2021
Kristen's poster entitled "Hyperglycemia delays ER export of proinsulin via altered ER redox homeostasis" is on display in the MERF-PBDB skyway connector (2nd floor). This work details the observation that proinsulin export from the ER is delayed in beta-cells cultured with elevated glucose and fatty acid. Included in this work are some stunning images of proinsulin trafficking using our SNAPtag model system and identification of proinsulin interactions by proximity labeling with APEX2 performed in collaboration with the Proteomics Core Facility.
Great job Kristen!
Ashleigh Machado receives ICRU fellowship, 2020
Ashleigh is an undergraduate research assistant in the lab who was awarded an Iowa Center for Research by Undergraduates (ICRU) fellowship. She will be developing genetically encoded sensors to explore the role of organelle pH in the regulation of insulin granule trafficking.
Casey Bauchle departs for Ph.D. training at the University of Virginia, 2020
Casey has been a research technician in the lab since 2018 and has been an outstanding member of our group. He has made numerous contributions to the research, which thus far have proven to be instrumental in many of the initiatives we are now following. Casey is now embarking on the next steps in his training at the University of Virginia where I have no doubt that he will excel. We will genuinely miss him.
Best of luck Casey!
Kristen Rohli joins the Stephens lab, 2020
Kristen joins the Stephens lab from the Interdisciplinary Graduate Program in Genetics for her Ph.D. training
Cierra Boyer joins the Stephens lab, 2020
Cierra joins the Stephens lab from the Pharmacology graduate program for her Ph.D. training
Dr. Stephens receives an American Diabetes Association Individual Basic Science Award, 2020
The major goal of this proposal is to address a significant gap in our understanding of insulin granule assembly and trafficking, provide mechanistic insight into how VGF and CgB regulate β-cell function, and define how VGF and CgB contribute to β-cell secretory capacity in T2D.
Dr. Stephens receives Carver College of Medicine Innovator award, 2020
This project aims to investigate the contribution of metabolism to changes in β-cell secretory function.
Dr. Stephens receives Department of Defense award, 2020
These studies will explore secretory trafficking dysfunction as a central mechanism in the progressive decline of β-cell function in the pathogenesis of Type 2 diabetes.
Marshall Moyer earns a research track distinction with his MD, 2020
Marshall Moyer received his MD degree from the University of Iowa and was awarded the research track distinction for his work in the lab on developing a system to study proinsulin interactions in models of β-cell dysfunction.
McKenzie Becker receives her B.S. in Chemistry, 2019,
McKenzie Becker has been an undergraduate research assistant in the lab for the past 2 years and has been instrumental in cloning many of the reporters and plasmid backbones we will use for years to come.
Weston Elison joins us for a summer research fellowship from BYU, 2019
Weston is a rising junior from BYU who was awarded a fellowship through the BYU Inspiring Learning Fellowship program. Weston will work on developing a cell culture model of the diabetic β-cell using exposure to elevated glucose and lipids to mimic hyperglycemia and hyperlipidemia present in human Type 2 diabetes.
Marshall Moyer joins us again for a summer research fellowship, 2019
Marshall's research project will be to map out novel protein interactions necessary for insulin trafficking within the pancreatic islet β-cell. To do this, we are using a proximity labeling system (APEX) to enzymatically tag proteins interacting with proinsulin. This approach will provide us with both spatial and temporal resolution of key mediators regulating insulin trafficking and allow us to investigate how these interactions are altered in pathological states of β-cell dysfunction such as Type 2 diabetes.
Welcome back Marshall!
Shelby Bearrows is featured in an interview for her recent publication in the Journal of Cell Science, 2019
Shelby was selected for an interview as an opportunity to promote early-stage career researchers for first author trainees. Congratulations Shelby!
"Chromogranin B regulates early stage insulin granule trafficking from the Golgi in pancreatic islet β-cells" published in Journal of Cell Science, 2019
This study highlights a specific role for chromogranin B (CgB) in the regulation of insulin granule formation at the trans-Golgi network utilizing a novel in situ fluorescent pulse-chase imaging technique to study insulin trafficking. Images from this work were selected for cover art for the July edition of JCS.
Visit our image of β-cells on display in the CBRB hallway, 2018
A confocal image generated by Shelby Bearrows from immunostained β-cells and spatially rendered using Imaris software was selected for display on the lower level hallway of the Pappajohn Biomedical Research Building.
Shelby Bearrows wins oral presentation at the Midwest Islet Club meeting, 2018
Shelby presented her research entitled “Chromogranin B regulates early stage granule trafficking from the trans-Golgi network in pancreatic islet β-cells” at the 11th annual Midwest Islet Club meeting in St. Louis, MO. Shelby was selected for the Best Oral Presentation Award.
Dr. Stephens receives Central Microscopy Research Facility Pilot Grant, 2018
This project aims to develop a novel fluorescent pulse-chase reporter for evaluating proinsulin trafficking.
"The prohormone VGF regulates β-cell function via insulin secretory granule biogenesis" published in Cell Reports, 2017
The paper describes a novel role of the prohormone and granin-like protein VGF in the regulation of secretory granule formation and insulin secretion in pancreatic islet beta-cells.
Marshall Moyer receives a summer research fellowship, 2017
Marshall will examine the insulinotropic actions of a novel peptide, TLQP-21, using mouse models lacking the putative TLQP-21 receptor, C3aR1.
"Delayed apoptosis allows islet β-cells to implement an autophagic mechanism to promote cell survival" published in PLoS One, 2017
This paper describes a novel feature of primary islet β-cells to be highly resistant to ER stress and DNA damage-induced apoptosis, which has garnered little attention in the literature. While β-cell survival and death pathways are commonly modeled in insulinoma cell lines, we demonstrate these events to be quite distinct between isolated islets and insulinoma cells.