Deubiquitinases: A Backdoor into Undruggable Targets?

Molecular model of the yeast proteasome.

Molecular model of the yeast proteasome.

Ubiquitin modification of a protein directs events such as targeting for proteasomal degradation. Targeting a protein for degradation through ubiquitin modification is one way to regulate the amount of time a signaling protein, such as a kinase or other enzyme, is available to participate in cell signaling events. Deubiquitinases (DUBs) are enzymes that cleave the ubiquitin tags from proteins, and they have been implicated in several diseases, including cancer.

With their roles in the stabilization of proteins involved in cell cycle progression and other critical processes, DUBs are promising targets for small molecule inhibitors, particularly since they may provide a “back door” for targeting otherwise intractable, undruggable proteins by modulating their half lives. However, finding small molecule inhibitors of the ubiquitin proteases to date has not been trivial. Here we highlight two papers describing the identification and characterization of small molecule inhibitors against the DUB USP7. Continue reading

Activating the Inflammasome: A New Tool Brings New Understanding

Innate immunity, the first line of immune defense, uses a system of host pattern recognition receptors (PRRs) to recognize signals of “danger” including invariant pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). These signals in turn recruit and assemble protein complexes called inflammasomes, resulting in the activation of caspase-1, the processing and release of the pro-inflammatory cytokines IL-1ß and IL-18, and the induction of programmed, lytic cell death known as pyroptosis.

Innate immunity and the activity of the inflammasome are critical for successful immunity against a myriad of environmental pathogens. However dysregulation of inflammasome activity is associated with many inflammatory diseases including type 2 diabetes, obesity-induced asthma, and insulin resistance. Recently, aberrant NLRP3 inflammasome activity also has been associated with age-related macular degeneration and Alzheimer disease. Understanding the players and regulators involved in inflammasome activity and regulation may provide additional therapeutic targets for these diseases.

Currently inflammasome activation is monitored using antibody-based techniques such as Western blotting or ELISA’s to detect processed caspase-1 or processed IL-1ß. These techniques are tedious and are only indirect measures of caspase activity. Further, gaining information about kinetics—relating inflammasome assembly, caspase-1 activation and pyroptosis in time—is very difficult using these methods. O’Brien et al. describe a one-step, high-throughput method that enables the direct measurement of caspase-1 activity. The assay can be multiplexed with a fluorescent viability assay, providing information about the timing of cell death and caspase-1 activity from the same sample. Continue reading

Genes to Cells to Genomes: Where Will Your Research Questions Take You?

Award presentation

Dr. Walter Blum wins trip to Promega headquarters as part of Promega Switzerland’s 25th Anniversary celebration.

Walter Blum knew how normal cells worked. He had studied and read about the pathways that regulated cell cycles, growth and development; he saw the cell as an amazingly well programmed, intricate machine. What he wanted to understand was: “Why does a cell become crazy? How does it escape immune system surveillance?”

Last week I had the opportunity to sit down with Dr. Blum, a customer of our Promega Switzerland branch. Dr. Blum won a trip to visit our campus in Madison for a week as part of an anniversary celebration for our Switzerland branch. While here, he got an inside peek at research and manufacturing operations, chatted with our scientists, met with our marketing teams and saw the sights in Madison. We talked about his work and what he learned and is taking back with him from his trip to Madison. Continue reading

An Unexpected History Lesson

Hillside Trail, Muir Woods National Monument

Hiking the Hillside Trail in Muir Woods National Monument

This land is your land, this land is my land
From California to the New York Island
From the Redwood Forest, to the Gulf stream waters
This land was made for you and me

–Woodie Guthrie

When my daughter was in preschool, she learned the lyrics to Woodie Guthrie’s folk song This Land Is Your Land. After one summer vacation, while she played in the Gulf stream waters off the coast of Florida, she asked, “Can we go see the Redwood Forest now?”

I had never seen the Redwood Forest, and my daughter’s request piqued my curiosity. I thought about my own childhood, when I had accompanied my older sister on a botany class project to collect plants and how curious I was about the plants and where they grew and what their names meant. Suddenly I wanted to see the Redwoods, and the Giant Sequoias.

It took a few years, but we managed to design a vacation trip that satisfied my daughter’s request to see the Redwood Forest and my growing curiosity, and I am so glad we did.  Continue reading

Just in Time for Wisconsin’s Invasive Species Month: Goats

Invasive kudzu vine

Invasive kudzu vine covering a forest

“In Georgia, the legend says
That you must close your windows
At night to keep it out of the house
The glass is tinged with green, even so
As tendrils crawl over the fields…”
—James Dickey (1)

I grew up in Georgia, where on a hot, humid summer day you could almost hear the hiss of growing vegetation, especially the Kudzu as it climbed over fence posts and encroached upon the roadside, the king of invasive species. In Florida you worry about the alligators along the roadside if you have a flat tire; in Georgia, beware the Kudzu.

Invasive species, animal and plant, are an issue in all ecosytems. Imported from distant (and not-so-distant) areas both by accident and misguided intent, invasive species are species that have escaped the checks and balances of natural competitors and predators that existed in their native habitats. This lack of predation and competition enables them to outcompete and overrun other species.

Kudzu may be one of the most recognized invasive species in the United States, but it’s probably not the worst. The zebra mussel is an aquatic animal that has invaded our waterways in Wisconsin. Oak savannahs and prairie ecosystems in the Midwest United States are threatened by many invasive plant species like garlic mustard and blister parsnip. The Wisconsin DNR lists nearly 150 restricted and/or prohibited invasive plant species in Wisconsin, including Kudzu (2). Continue reading

March for Science—Every Day

Kindergarten teacher and children looking at bird's nest in librEarth Day, April 22, saw one of many of the marches on Washington, D.C. that 2017 has produced: The March for Science.

A march is a shout, a “Hey, over here, you need to hear this” one-time event. It is not a conversation. It really isn’t even action. It’s a start that requires follow up.

But how do you follow up a massive, organized march that happened across the globe? Consider following it up with little things, at every opportunity:

First, say “yes” to opportunities to be an ambassador for science. Continue reading

A Cold Case, A Mystery, and DNA

“How do you like the name Jack?” the woman on the phone asked.

41731849 - soft focus and blurry of baby hands vintage style color effectOn April 26, 1964, a nurse came into the hospital room of Dora Fronczak, who had just given birth to her young son, Paul. She told Mrs. Fronczak that it was time to take the baby to the nursery (at that time newborns did not stay in the room with the moms), took the baby, and left. A few hours later, another nurse came into the room to take young Paul to the nursery. It was then that everyone realized a mother’s worst fear: Her infant had been stolen.

Authorities were able to determine how the woman left the hospital and that she got into a cab, but they were never able to find the woman. However in 1965, a small toddler-aged boy was found, abandoned outside a store in New Jersey. Blood tests were not inconsistent with him being Paul Fronczak (DNA testing was not available), and there were no other missing children cases in the area that were matches. The little boy was sent to Chicago as Paul Fronczak and the case was closed.

However, as an adult Paul Fronczak, began to suspect that the couple who raised him were not his biological parents, and in 2012 Paul underwent DNA analysis to test his suspicions. The results showed that indeed, he was not the biological son of Dora and Chester Fronczak. His next step was to enlist the help of a genetic genealogist to assist him in finding his true biological parents and his identity.

By conducting “familial searches” using commercially available DNA databases like 23andMe and AncestryDNA and many resources, the genealogist’s group found a match to his DNA on the east coast. Further ground work, discovered that this family was indeed Paul’s…now Jack.

The knowledge of Jack’s true identity, didn’t bring with it a joyous union of the adoptive family who had raised and loved Jack (as Paul) with the biological family who had pined for him over the years as many might imagine. Continue reading

Calling All Science PUNdits

As the point of contact for our social media efforts at Promega, I spend a lot of time scanning science-related Twitter, Facebook, Instagram media accounts. There are some science channel managers who do a great job of bringing delight to their followers. Those managers use their platforms to educate—I follow them because they constantly amaze me with new things. I find information that is useful, fun and makes me think “wow, that is interesting.” On my favorite accounts, that new learning comes along with a wry sense of humor, and some of my favorite social media channels are ones that not only teach me new things but do it with a little fun on the side—often in the form of bad science puns.

Promega has the privilege of sponsoring the Cool Science Image contest run by the University of Wisconsin-Madison. Just recently @UWMadScience tweeted about the deadline for the contest, tagging @promega in the tweet. Their tweet included a visual science pun which was not lost on their fellow campus account managers:


That pun started a chain reaction among the other UW accounts that follow @UWMadScience: Continue reading

Weaving Tangled Webs with Cell-Free DNA

The ability to isolate and assay circulating cell-free DNA from plasma holds promise for improved diagnostics and treatment in the clinic. The use of blood-based non-invasive prenatal testing (NIPT) has been well described. Such testing is based on circulating cell-free fetal DNA in blood of a pregnant woman for diagnosis and screening  of chromosomal anueploidy (e.g. Trisomy 21, Down Syndrome), sex-linked diseases, and genetic diseases that are known to result from a specific mutation in a single gene (1). Additionally, most cancers carry somatic mutations that are unique to the tumors, and dying tumor cells release small pieces of their DNA into the blood stream (2). This circulating cell-free tumor DNA can be used as a biomarker to “follow” cancer progression or regression during treatment, and diagnostic methods also are being developed to detect even early stage cancers from circulating tumor DNA (3). Further, increases in circulating cell-free DNA have been well documented after intense exercise, trauma, sepsis and even associated with autoimmune diseases such as system lupus erythematosus (SLE; 1,4). In these latter examples increases in extracellular DNA are associated with evolutionarily conserved innate immune responses involving the production of neutrophil extracellular traps (NETs). Monitoring the circulating cell-free DNA of NETs has implications for treatment and diagnosis of autoimmune diseases, cardiovascular events and traumatic injuries (4–7).

How Neutrophils Weave a Defensive Web

Blood smear showing two prominent neutrophils in the field of view

Blood smear showing two prominent neutrophils in the field of view

Neutrophils are the most abundant type of white blood cell and are part of the innate immune response, participating in non-specific immune responses to injury or pathogens. They are one of three types of granuolcytes, and can be recognized by their multi-lobed nucleus and the prominent granules that fill their cytoplasm. Generally they are first to the scene of injury or infection. Early in my scientific career, I was taught that neutrophils fought disease via phagocytosis and occasionally by firing a barrage of toxic enzymes and molecules at invaders. Mostly though they released cytokines that recruited the “important” cells of the specific immune system to the area.

For these reasons, I never really thought much about neutrophils. That is until recently, when I learned about Neutrophil Extracellular Traps (NETs). It turns out that neutrophils are pretty awesome, sacrificing themselves in a cloud-like explosion of DNA, chromatin, and granule proteins Continue reading

Deciding What to Share: Evaluating Content in a Self-Publishing World

A BuzzFeed News analysis of “news” stories during the final three months of the 2016 US presidential campaign revealed that on Facebook, the 20 top-performing fake-news stories from hoax sites and hyper partisan blogs generated 8,711,000 instances of engagement (shares, reactions, or comments) while the 20 top-performing stories from news web sites generated 7,367,000 instances of engagement (1). Basically fake news generated 1.5 million more responses than real news.

This is particularly concerning given that a Pew Research study from July 2016 indicated that 63% of Americans say that family and friends are an important way they get news—they get their news from their social networks (online or offline) rather than from vetted broadcast or print media (2), and 54% of people asked in this same study responded that they “sometimes” or “often” received news from social networking sites such as Facebook or Twitter.

I too must confess that quite often it’s a tweet or a Facebook post that alerts me to a news story or world event. Often it’s even a tweet or a post that leads me to the latest science news. I can’t remember the last time I deliberately watched the 6:00 news, though it was a staple in my house when I was growing up.

So what does all of this mean for science communication, science literacy and a basic understanding of what is really going on in the world? Continue reading