A Protein Controlled by both Light and Temperature May Open Doors to Understanding Disease-related Cell Signal Pathways

by Melissa Pappas

The brighter edges of the cells in the middle and upper right panels show the optogenetic proteins collecting at the membrane after light exposure. At higher temperatures, however, the proteins become rapidly inactivated and thus do not stay at the membrane, resulting in the duller edges seen in the bottom right panel.

Most organisms have proteins that react to light. Even creatures that don’t have eyes or other visual organs use these proteins to regulate many cellular processes, such as transcription, translation, cell growth and cell survival.

The field of optogenetics relies on such proteins to better understand and manipulate these processes. Using lasers and genetically engineered versions of these naturally occurring proteins, known as probes, researchers can precisely activate and deactivate a variety of cellular pathways, just like flipping a switch.

Now, Penn Engineering researchers have described a new type of optogenetic protein that can be controlled not only by light, but also by temperature, allowing for a higher degree of control in the manipulation of cellular pathways. The research will open new horizons for both basic science and translational research.

Lukasz Bugaj, Bomyi Lim, and Brian Chow

Lukasz Bugaj, Assistant Professor in Bioengineering (BE), Bomyi Lim, Assistant Professor in Chemical and Biomolecular Engineering, Brian Chow, Associate Professor in BE, and graduate students William Benman in Bugaj’s lab, Hao Deng in Lim’s lab, and Erin Berlew and Ivan Kuznetsov in Chow’s lab, published their study in Nature Chemical Biology. Arndt Siekmann, Associate Professor of Cell and Developmental Biology at the Perelman School of Medicine, and Caitlyn Parker, a research technician in his lab, also contributed to this research.

The team’s original aim was to develop a single-component probe that would be able to manipulate specific cellular pathways more efficiently. The model for their probe was a protein called BcLOV4, and through further investigation of this protein’s function, they made a fortuitous discovery: that the protein is controlled by both light and temperature.

Read more in Penn Engineering Today.

Engineering and Medicine Researchers Collaborate on Studies of Genome Folding in Health and Disease

(Left to right) Top row: Jennifer E. Phillips-Cremins, Rajan Jain, and Eric Joyce. Middle row: Melike Lakadamyali, Golnaz Vahedi, and Gerd Blobel. Bottom row: Bomyi Lim, Arjun Raj, and Stanley Qi.

Popular accounts of the human genome often depict it as a long string of DNA base pairs, but in reality the genome is separated into chromosomes that are tightly twisted and coiled into complex three-dimensional structures. These structures create a myriad of connections between sites on the genome that would be distant from one another if stretched out end-to-end. These “long range interactions” are not incidental — they regulate the activity of our genes during development and can cause disease when disrupted.

Now two teams of researchers at the Perelman School of Medicine at the University of Pennsylvania, each led by Jennifer E. Phillips-Cremins,  associate professor and Dean’s Faculty Fellow in the Department of Bioengineering at the School of Engineering and Applied Science and of Genetics at the Perelman School of Medicine have been awarded grants totaling $9 million from the National Institutes of Health (NIH), as part of a major NIH Common Fund initiative to understand such 3D-genomic interactions.

The initiative, known as the 4D Nucleome Program, broadly aims to map higher-order genome structures across space and time, as well as to understand how the twists and loops of the DNA sequence govern genome function and cellular phenotype in health and disease.

Read the full story in Penn Engineering Today.

N.B.: In addition to Phillips-Cremins, collaborators include Arjun Raj, Professor in Bioengineering and Genetics, and Bioengineering Graduate Group Members Melike Lakadamyali, Associate Professor in Physiology, and Bomyi Lim, Assistant Professor in Chemical and Biomolecular Engineering.

Bomyi Lim Receives KIChE President Young Investigator

Bomyi Lim, Ph.D.

Bomyi Lim, Assistant Professor in the Department of Chemical Biomolecular Engineering, has been selected by the U.S. Chapter of the Korean Institute of Chemical Engineers (KIChE) as the recipient of the KIChE President Young Investigator Award. As a recipient of this Award, Lim will be invited to present a research talk at the KIChE Open Forum during the AIChE Conference.

KIChE is an organization that aims “to promote constructive and mutually beneficial interactions among Korean Chemical Engineers in the U.S. and facilitate international collaboration between engineers in the U.S. and Korea.”

Read more on the Penn Engineering blog. Dr. Lim is a member of the Department of Bioengineering Graduate Group.