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The collection of proteins within a cell determines its health and function. Proteins are responsible for nearly every task of cellular life, including cell shape and inner organization, product manufacture and waste cleanup, and routine maintenance. Proteins also receive signals from outside the cell and mobilize intracellular response. They are the workhorse macromolecules of the cell and are as diverse as the functions they serve.

This flipped case was designed to introduce students in a general introductory biology course to basic protein structure. The two videos and interrupted case use keratins in hair as model proteins. From the videos students learn how amino acids regulate protein structure, and how small changes in amino acid sequence have large impacts on overall protein organization and function. The case story focuses on a puppy whose hair changes from straight to curly when it sheds its coat. The protagonist tests the adult versus puppy hair, and discovers that the amino acid composition is different in the curly versus straight hair samples. Students apply basic principles of protein structure to hypothesize why the dog's coat switched from straight to curly. The case intentionally stops short of providing a complete answer to the mystery, so students think through the molecular processes logically rather than having a final "correct" answer. An optional activity is provided that makes the case more appropriate for an introductory cell biology class.

This directed case study examines the molecular basis of cystic fibrosis to emphasize the relationship between the genetic code stored in a DNA sequence and the encoded protein's structure and function. Cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein that functions to help maintain salt and water balance along the surface of the lung and gastrointestinal tract. This case introduces students to "Maggie," who has just been diagnosed with cystic fibrosis. The students must identify the mutation causing Maggie's disease by transcribing and translating a portion of the wildtype and mutated CFTR gene. Students then compare the three-dimensional structures of the resulting proteins to better understand the effect a single amino acid mutation can have on the overall shape of a protein. Students also review the concepts of tonicity and osmosis to examine how the defective CFTR protein leads to an increase in the viscosity of mucus in cystic fibrosis patients. This case was developed for use in an introductory college-level biology course but could also be adapted for use in an upper-level cell or molecular biology course.

Current CRISPR-based screens often mutate the beginning of a gene, which sometimes results in the expression of a functional protein variant. To circumvent this problem, researchers at Cold Spring Harbor Laboratory (CSHL) designed CRISPR guide RNAs that would mutate the portion of a gene encoding a domain on the surface of the protein where a small molecule could bind to alter the protein's function. The team had previously identified such a binding pocket on the protein BRD4, and a small molecule inhibitor that binds in the pocket is an effective leukemia treatment.

This interrupted case study examines basic concepts of chemical bonding by telling the story of "Madison," a young girl eager to learn how her hair can transition from natural curls to straight, smooth tresses. The case can be used to teach or review the major categories of bonds (ionic, covalent and hydrogen), major macromolecules of life, and hydrolytic and dehydration reactions. It also explores how chemical relaxers and heat through blow drying and flat-ironing can change the nature of straight, wavy and curly hair through the disruption of protein shape. Students will thus learn what it means when a protein has become denatured and how various variables such as pH, heat and salts can lead to the unraveling of the three-dimensional shape of proteins. This case is suitable for an AP high school course, or for an introductory biology or chemistry course for majors or non-majors. This activity can also be used as a review of basic biology and chemistry for students in an upper-level biochemistry course.

This clicker case study follows a dialogue between two college students, Lucy and Dan, as they discover how alternative splicing of mRNA molecules can allow a single gene to code for multiple proteins. Dan is participating in a clinical trial for a drug that may treat his migraines by inhibiting calcitonin gene-related peptide, and Lucy is working in a summer research lab that studies the protein calcitonin. They soon realize that the two proteins are both encoded by the same gene, and through their questioning and dialogue they come to understand the phenomenon of alternative splicing. They also learn about other steps of mRNA processing and about monoclonal antibodies. This case was designed to be taught in a flipped classroom, but could easily be adapted for a more traditional classroom setting if content covered in the pre-class videos is covered during the case study instead. It was designed for an introductory-level molecular biology course, but could be adapted for higher levels by including more information about the physiology and regulatory mechanisms involved.

A team of Indian biologists has demonstrated that a key component of the water buffalo genome can be manipulated to produce foreign proteins in the buffalo's milk (J. Biotechnol. 2015, DOI:10.1016/j.jbiotec.2015.02.001). The findings suggest the possibility of modifying the genetic material of water buffalo-that is, creating transgenic buffalo-to produce protein drugs, says team member Subeer S. Majumdar, of the National Institute of Immunology, in New Delhi.

Venom - information on protein structure and function, following scenario of a scorpion bite.  Interactive game and activities included on site.

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.

This case study synthesizes students' knowledge of the central dogma and cell structure by examining a rare health disorder in order to understand protein targeting and its medical consequences. Students first identify the molecular alteration in affected members of a family with renal Fanconi syndrome as reported in the New England Journal of Medicine (2014). Students then use an online bioinformatics tool to analyze the wildtype and mutant proteins and examine their subcellular localization. Finally, students use this information to explain the symptoms of affected family members. The case is delivered with a PowerPoint presentation that includes a selection of brainstorming prompts and "clicker questions." Students complete a worksheet (included in the teaching notes) before class, making the activity suitable for a flipped classroom. A second worksheet (also included in the teaching notes) is completed during class. The case is written for an introductory biology course for majors, but could also be used as a unit capstone in a non-majors human biology course; the case is also scalable to upper division courses in physiology that specifically explore kidney function.

Your cells contain an amazing factory that builds the RNA and protein machines that keep you alive. Learn how this factory works and what the relationship is between DNA, RNA, and proteins.

She wanted to understand the effects of mutations that the gene for p53 is prone to. In dozens of simulations, she and her colleagues tracked how common p53 mutations further destabilize the already floppy protein, distorting it and preventing it from binding to DNA. Some simulations also revealed something else: a fingerhold for a potential drug. Once in a while, a small cleft forms in the mutated protein's core. When Amaro added virtual drug molecules into her models, the compounds lodged in that cleft, stabilizing p53 just enough to allow it to resume its normal functions.

Because the gene-enzyme system forms a closed loop, it presents us with a classic chicken or egg conundrum: Which came first, genes or the protein enzymes they code for? While the details are still not fully worked out, discoveries over the past few decades have lead researchers to a surprising possible solution: What really came first? Genes that act as enzymes! The RNA World Hypothesis is the idea that before living cells, the genetic code, and the gene/protein cycle ever existed, chains of a chemical called RNA were forming naturally. Once formed, some of these chains were able to function as enzymes, and were even able to evolve by making copies of themselves with slight, accidental modifications.

3:35 minute video trailer for protein synthesis

The most recent human retroviral infections leading to germ line integration took place with a subgroup of human endogenous retroviruses called HERVK(HML-2). The human genome contains ~90 copies of these viral genomes, which might have infected human ancestors as recently as 200,000 years ago. HERVs do not produce infectious virus: not only is the viral genome silenced - no mRNAs are produced - but they are littered with lethal mutations that have accumulated over time. A recent study revealed that HERVK mRNAs are produced during normal human embryogenesis. Viral RNAs were detected beginning at the 8-cell stage, through epiblast cells in preimplantation embryos, until formation of embryonic stem cells (illustrated). At this point the production of HERVK mRNA ceases. Viral capsid protein was detected in blastocysts, and electron microscopy revealed the presence of virus-like particles similar to those found in reconstructed HERVK particles. These results indicate that retroviral proteins and particles are present during human development, up until implantation.

Before the discovery of insulin in 1921, being diagnosed with Type 1 diabetes was a death sentence. Despite the successful management of diabetes with purified animal insulin, potentially severe side effects were abundant, and alternative ways to produce insulin were needed. This case study guides students through the history of using insulin to treat diabetes, focusing on the development of recombinant DNA technology and the world's first bioengineered drug, recombinant human insulin, which is now used worldwide to treat diabetes. Through the course of this case, students consider the central dogma of molecular biology, the development of recombinant DNA technology, drug design, the importance of recombinant proteins to our society, and the ethical analysis and debates that occur as a result of some scientific discoveries. This case was developed as an introduction to an upper-division biotechnology course focusing on recombinant protein design and production, but could also be used in molecular biology, biochemistry, or introductory biology courses to highlight recombinant DNA and biotechnology.

In a new study, researchers have made insights into how the blood-brain barrier, or BBB, is maintained, identifying a protein key to the process. Delivering this protein to mice with the rodent equivalent of MS improved their symptoms.

3:35 video To some they look like bow-legged cowboys. To others, swaggering pirates. Either way, the two-legged molecules known as motor proteins are what get the job of living done in most of your cells.

Why did you get the flu this winter, but your co-workers didn't? The answer, according to a new study of twins, may have less to do with your genes and more to do with your environment-including your past exposure to pathogens and vaccines. Our immune system is incredibly complex, with diverse armies of white blood cells and signal-sending proteins coursing through our veins, ready to mount an attack on would-be invaders. Everyone's immune system is slightly different-a unique mixture of hundreds of these cells and proteins. But the main driver of this variation is unclear. Although scientists know that our immune system can adapt to our environment-that's why vaccines work, for instance-it is also built by our genes.

Naked mole rats are hairless, blind, underground dwellers that are remarkably impervious to cancer. But why you ask? Well, researchers at the University of Rochester asked that same question and it turns out a cluster of genes, called the INK4 locus, is the answer. This locus, also found in humans and mice, uses that cluster to carry instructions, or encode, for several cancer fighting proteins.