headshot of Daniel Portnoy

Research Expertise and Interest

microbiology, bacteriology, infectious diseases, intracellular pathogens, innate immunity, adaptive immunity, vaccines, cell biology

Research Description

Daniel Portnoy is a professor of Biochemistry, Biophysics, and Structural Biology in the Department of Molecular and Cell Biology and the Department of Plant & Microbial Biology.  

Intracellular pathogens are responsible for an enormous amount of worldwide morbidity and mortality and the development of vaccines and therapeutics to treat diseases caused by these pathogens continues to represent one of the biggest challenges facing the international biomedical community. By virtue of their intracellular niche, these pathogens avoid extracellular immune defense mechanisms, and consequently, vaccine strategies that target the production of antibodies have been largely ineffective. The Portnoy lab tackles a wide range of problems related to the pathogenesis and host response to intracellular pathogens with the goal of developing vaccines and therapeutics. Specifically, the lab works on Listeria monocytogenes, a facultative intracellular food-borne bacterial pathogen that is an outstanding model system with which to dissect basic aspects of host-pathogen interactions. 

Specifically, the lab is focused on the interaction of the facultative intracellular bacterial pathogen Listeria monocytogenes and its mammalian host. This fascinating microorganism is able to enter cells, escape from a phagosome, circumvent autophagy, avoid cell death pathways, and grow rapidly in the cytosol. By exploiting a host system of actin-based motility, the bacteria move through the cytosol to the cell membrane and into pseudopod-like projections (listeriopods) that are ingested by neighboring cells. This mechanism allows pathogens to spread from one cell to another without ever leaving the host cytoplasm thereby avoiding the immune response. Current research covers many topics including basic microbiology, the cell biology of infection, innate immune responses, acquired immunity, and vaccine development to both infectious diseases and cancer.

In the News

Three innovators elected to National Academy of Inventors

Three faculty members – Tsu-Jae King Liu and Eli Yablonovitch of electrical engineering and computer sciences and Daniel Portnoy of molecular and cell biology and public health – have been named fellows of the National Academy of Inventors.

The yin-yang of cancer and infectious disease

Doctors have had great success using vaccines to boost the immune system to fight infectious diseases like smallpox and measles, but only recently have immune system boosters been tried against cancer.

Three faculty members named to National Academy of Sciences

In recognition of their excellence in original scientific research, three UC Berkeley faculty members have been elected members of the National Academy of Sciences (NAS), one of the highest honors given to a scientist or engineer in the United States.

New bacterial signaling molecule could lead to improved vaccines

In a 20-year quest to determine why Listeria bacteria produce a uniquely strong immune response in humans, UC Berkeley scientists have found part of the answer: an unsuspected signaling molecule that the bacteria pump out and which ramps up production of interferon by the host. Interferon mobilizes the immune system to fight off bacteria and viruses.

Featured in the Media

Please note: The views and opinions expressed in these articles are those of the authors and do not necessarily reflect the official policy or positions of UC Berkeley.
September 13, 2018
Yasemin Saplakoglu

Some of the bacteria in our gut, including ones that are used to ferment yogurt or probiotics, generate electricity, a team of Berkeley researchers has discovered. While so-called "electrogenic" bacteria are known to exist in remote places, like the bottom of lakes, it wasn't previously known that bacteria in decaying plants, or in mammals, were also creating electricity, and in a much simpler way, says molecular and cell biology professor Daniel Portnoy, the study's senior author. While the key reason for bacteria to do this is in order to create energy, it may also remove electrons produced by metabolism, Professor Portnoy says. And, according to postdoctoral researcher Sam Light, the study's lead author, it is "probably a back-up system that they use under certain conditions," like the low-oxygen environment of the gut. While raising all kinds of new questions about the body and life on Earth, the study is also spurring interest as a new path for renewable energy technologies. For more on this, see our press release at Berkeley News. Stories on this topic have appeared in a couple dozen sources, including Medicine News Line, Daily Mail Online, and Research & Development.

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