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A Different Kind of Stress

Protein Trafficking and the Unfolded Protein Response


Karen S. Huffman
Erie Community College


Protein folding and trafficking is essential for normal cell function, and when it goes awry it can lead to various chronic conditions, including fatty liver disease, diabetes, and Parkinson's. The narrative of this case study follows two undergraduate students engaged in a summer research project evaluating the effects of cell stress on cell function and health in the model organism Caenorhabditis elegans (C. elegans).  During the case study, students review animal cell organelle function and then learn about endoplasmic stress and unfolded protein response. Prior knowledge needed for the case is basic animal cell organelles and their functions and use of model organisms in research. The case was designed for a flipped classroom in which students prepare in advance by taking a quiz and watching two videos; a PowerPoint animation is also included. Originally written for a non-majors biology class, the case could also be used for a first year majors' class.


  • Understand and explain basic animal organelles and their functions.
  • Describe the process and function of protein trafficking.
  • Describe the outcomes of endoplasmic stress and unfolded protein response.
  • Explain apoptosis.
  • Explain the association of disease and disruption to normal organelle functions.


Organelles; protein trafficking; protein folding; unfolded protein response; apoptosis; model organism; endoplasmic stress; C. elegans

Educational Level

High school, Undergraduate lower division



Type Methods

Directed, Flipped, Interrupted



Subject Headings

Biology (General)  |   Cell Biology  |   Molecular Biology  |  

Date Posted


Teaching Notes

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Supplemental Materials

Students view the following PowerPoint presentation during Part III of the case.


Answer Key

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The following video(s) are recommended for use in association with this case study.

  • C. elegans Movement
    This video shows normal Caenorhabditis elegans movement. Running time: 5:27 min. Uploaded to YouTube by BioRadLifeScience, 2013.
  • Protein Trafficking Through the Golgi
    This video provides an overview of protein movement from the rough endoplasmic reticulum (RER) to the Golgi for modification. Running time: 3:27 min. Produced by Virtual Cell Project, Virtual Cell Animation Collection, Molecular and Cellular Biology Learning Center, North Dakota State University.