George Stark’s enthusiasm for understanding
signaling pathways and developing
biochemical methods is infectious.
|George Stark remains committed to developing methods and understanding the fundamentals of signaling pathways. Photo courtesy of George Stark
George Stark of the Cleveland Clinic is as comfortable in a kitchen as he is in a laboratory. The son of a restaurant owner, Stark says, “learning how to handle myself in a restaurant was good training for how to be a good chemist.” In fact, an extremely good biochemist. Stark’s scientific accomplishments, such as the development of Northern blotting for detecting RNA and the discovery of the JAK-STAT signaling pathway, have garnered him many accolades, including the 2011 Herbert Tabor/Journal of Biological Chemistry Lectureship, awarded by the American Society for Biochemistry and Molecular Biology each year for excellence in biological chemistry and molecular biology (1).
As a boy in the 1940s, Stark spent hours working in his father’s eatery, Stark’s Beef and Beans, in Washington, D.C. Watching his father’s struggles made Stark decide at a young age that the restaurant business was not for him. His father agreed. His father, whom Stark describes as “a dominant personality … a go-out-and-get-’em business man,” had grand plans for his only son (Stark has two older sisters). “It was the typical ‘My son should be a doctor!’” says Stark with a laugh.
Stark’s mother was a quiet woman who worked as a bookkeeper to hold the family steady through the highs and lows of the restaurant business. His parents didn’t know much about science, Stark says, but, based on what they were aware of, they encouraged him to pursue medicine. To get the boy started, the family moved to New York City so Stark could attend the Bronx High School of Science for his senior year.
He went on to Columbia College for his undergraduate degree, but as he got more into his premedical school studies, Stark says, he realized he really wanted to do research, not medicine. A comparative anatomy class cemented the decision. “Looking at a bunch of pins stuck in a dissected frog and trying to remember the names of what was underneath each pin was daunting for me,” he says. “I can remember things very well if I can link them in a logical chain, but the names of all these nerves and so forth in the frog were not linkable in a logical chain for me!”
In what he calls an act of self-defense to avoid medical school, Stark stayed on at Columbia for graduate school in the laboratory of his undergraduate adviser, Charles Dawson, to study ascorbate oxidase from yellow crook-necked squash. In a Reflections article for The Journal of Biological Chemistry, Stark recalls spending happy hours in the cold room peeling mounds of the vegetable because the enzyme was concentrated in its skin (2).
Stark followed his graduate studies with a stint at The Rockefeller University as a postdoctoral fellow with soon-to-be Nobel laureates Stanford Moore and William Stein, who had invented the amino acid analyzer and sequenced bovine pancreatic ribonuclease. It was also during this time that Stark met a physicist who became his wife and, for several years, labmate. Stark has described Mary Beck as “the glue that holds one’s life together.”
Stark’s work on carbamylation to identify the amino-terminal residues of proteins and aspartate transcarbamylase attracted the attention of Arthur Kornberg, who recruited him to Stanford University in the early 1960s. There, in the 1970s, Stark’s group developed Northern blotting. At that time, RNA was detected by separating an RNA mixture in a tube gel, freezing the gel, and “putting it in a device like an egg slicer and cutting it into 100 or so pieces,” says Stark. Each gel piece was hybridized with a complementary RNA probe to see which gel piece contained the RNA in question. The method, Stark says, was “ridiculously cumbersome.” His group decided to do better.
They had figured out in 1975 how to make chemically reactive cellulose that would covalently bind to DNA and RNA (3). Stark’s group then made chemically reactive cellulose paper onto which they could attach RNA molecules from a gel. They then probed the entire paper with the complementary nucleic acid chain (4). “It actually worked the first time we tried it,” says Stark.
Stark’s sense of humor came through when they named the technique “Northern blotting” as a joke on Southern blotting, which Edwin Southern at Oxford University had developed for DNA detection (5). Similarly, Stark’s group did the first demonstration of the idea of transferring proteins out of gels for detection (6, 7).
It was also at Stanford that Stark’s group discovered PALA, an abbreviation for N-phosphonacetyl-L-aspartate (8). The molecule is the analog of aspartate transcarbamylase’s transition state. Stark’s group discovered that PALA was a strong inhibitor of aspartate transcarbamylase and that it could enter mammalian cells to block pyrimidine nucleotide biosynthesis.
With PALA, Stark and colleagues went on to discover the giant polypeptide CAD that contained aspartate transcarbamylase, carbamyl phosphate synthetase and dihydro-orotase, all involved in pyrimidine synthesis. By studying CAD, Stark’s group was one of the first to show gene amplification in mammalian cells.
An American in London
In 1983, after 20 years at Stanford, Stark landed in London at the Imperial Cancer Research
Fund. His research interests had moved from protein biochemistry to cellular and molecular biology, and he was interested in interferon-dependent signaling, an area in which he worked in collaboration with Ian Kerr at the U.K. Medical Research Council.
“London is a wonderful place to live,” says Stark. “We were very privileged, because we owned a house in California that we were basically able to trade for a nice house in central London.” Stark says that the environment at ICRF was also special. “My lab was completely funded. I didn’t have to write any grants. All I had to do was show up for a review every five years,” he explains. “It was heaven for somebody like me who wanted to primarily do research.”
Part of his group in London worked on mechanisms of gene amplification, and the rest worked on interferon signaling pathways, research that later led to the discovery of the JAK-STAT pathway (9). The group also developed an approach called validation-based insertional mutagenesis (10).
But Stark’s idyllic world was in for a nasty surprise nine years later. “I realized I was going to have to retire in the British system in a couple of more years!” he says. Stark would have had to have stopped working in 1995 at age 62.
Back in the U.S.
Determined not to be forced out, Stark found another position in 1992 at the Cleveland Clinic Foundation, where a vacancy popped up after Bernadine Healy moved to become head of the National Institutes of Health under President George H.W. Bush. Twenty years later, his laboratory still continues to forge ahead on interferons, STAT1 and NFκB research.
His group has found that the mutagenesis approach they have developed can be powerful. “It is a way to upregulate gene expression randomly in a population of cells,” explains Stark. “If upregulation of a protein in one cell out of millions in a population gives you an interesting phenotype and you have a way to find that cell by selection or something else, then that can lead to a novel research project.”
|Stark with his wife, Mary Beck; son, Robert; and daughter, Janna. Photo courtesy of George Stark.
For instance, Stark’s group has an interest in lysine methylation of transcription factors, a mechanism that affects gene expression. With the mutagenesis approach, “we found upregulation of a demethylase that affected the function of NFκB,” says Stark (11). “We’ve also used that method a lot in finding new mechanisms of drug resistance” (12).
Immersed as he is, Stark still manages to have a life outside of science. “I like to cook. I enjoy sports, mostly now as a viewer rather than a participant!” he says. “I love classical music. I did sing together with Mary a lot. We were in choruses in New York and California.” The Starks also are enthusiastic concert and theater goers and collect art pieces, such as Japanese prints and Inuit sculptures.
But Stark continues to be leery of retirement. He has reduced his load of administrative work so he can have more free time to spend with his family. But he is absolutely certain of one thing: “I don’t want to give up science,” he says. “I don’t want to quit.”
- 1. Zagorski, N. George Stark to give 2011 annual meeting opening lecture. ASBMB Today, January 2011.
- 2. Stark, G.R. J. Biol. Chem. 280, 9753 – 9760 (2005).
- 3. Noyes, B.E. & Stark, G.R. Cell 5, 301 – 310 (1975).
- 4. Renart, J.; Reiser, J.; & Stark, G.R. Proc. Natl. Acad. Sci. U.S.A. 76, 3116 – 3120 (1979).
- 5. Southern, E.M. J. Mol. Biol. 98, 503 – 517 (1975).
- 6. Alwine, J.C.; Kemp, D.J.; & Stark, G.R. Proc. Natl. Acad. Sci. U.S.A. 74, 5350 – 5354 (1977).
- 7. Mukhopadhyay, R. The men behind Western blotting. ASBMB Today, March 2012.
- 8. Kresge, N.; Simoni, R.D.; & Hill, R.L. J. Biol. Chem. 282, e23 (2007).
- 9. Kandel, E.S. et al. Proc. Natl. Acad. Sci. U.S.A. 102, 6425 – 6430 (2005).
- 10. Velazquez, L. et al. Cell 70, 313 – 322 (1992).
- 11. Tao, L. et al. Proc. Natl. Acad. Sci. U.S.A. 106, 16339 – 16344 (2009).
- 12. Canhui Guo & Stark, G.R. Proc. Natl. Acad. Sci. U.S.A. 108, 7968 – 7973 (2011).
Rajendrani Mukhopadhyay (firstname.lastname@example.org) is the senior science writer for ASBMB Today and the technical editor for The Journal of Biological Chemistry. Follow her on Twitter at @rajmukhop.