Professor Timothy J Mitchison
Doctor of Science, honoris causa (2022)
Professor Timothy John Mitchison is currently Hasib Sabbagh Professor of Systems Biology at Harvard University where, since 1997, he, his colleagues, and PhD students have established world-leading lab-based research in cell biology and systems pharmacology. Throughout his career, Mitchison has sought to communicate his love of science beyond the scientific guild, to convey to more general audiences the wonder of growth and form as the hurly-burly of cytoplasmic subcellular activity gives way to the precisely organised and ever more complex structures found in nature.
Professor Mitchison’s expertise inhabits precisely this crux between cellular processes and what he terms the more “highly ordered and precise” assemblages at larger scale. He reminds me that all any student needs to begin is a (unicellular) frog egg and a decent microscope. Over the years, Mitchison’s imagination has intervened boldly to illustrate the functional dynamism of processes attending cell division (mitosis), including cytoskeleton and cytoplasm self-organisation, as foundational tenets for his field. As a cherished former postdoctoral fellow told me, Mitchison is a “pure” scientist, an enabler of those around him, generous and always egalitarian when instilling the “exploratory spirit” of science. For his part, Mitchison credits his early mentors in California for imbuing him with the collective endeavour good science requires: “Only one-tenth [of the process] is ever you”, Mitchison declares, “the other nine-tenths belongs to your colleagues and students”.
Professor Mitchison took his BA in Biochemistry at Merton College (Oxford University) in 1980, followed by PhD studies in Biochemistry and Biophysics at the University of California San Francisco (UCSF). While at UCSF, Mitchison’s doctoral research was supervised by Marc Kirschner, under whose direction he first identified, then analysed, what he termed the “dynamic instability” of microtubules, including mapping the interactions occurring between microtubules and chromosomes during cell division (mitosis). Another mentor at UCSF, Bruce Alberts, a specialist in DNA and DNA replication, urged Mitchison to explore genetic pharmacology. By 1997 Mitchison was recruited away from UCSF to become director and co-founder of the Institute for Chemistry and Cell Biology (ICCB) at Harvard, the first of its kind in an academic setting. At ICCB, Mitchison and colleagues first piloted phenotype-based drug-screening techniques, whose “highthroughput” volume established the necessary “knockouts” of unwanted genetic constituents, hence accelerating prototyping for therapeutic development. Mitchison is duly credited as the creator of the tools of perturbation used to document patterned responses in subcellular environments as well as for their refinement to the purposes of therapeutic application.
Currently heading the lab at the Harvard Medical School Systems Biology Department, Professor Mitchison has enjoyed productive and happy collaboration with numerous students and colleagues.
His particular interests involve analysing the diverse mechanisms of cell division (cytokinesis) as well as the patterns, metabolic morphologies, cell sizes and shapes, and pharmacological cues in both normal and diseased cells. To date, Professor Mitchison’s research has had promising potential for the field of pharmacology and biotechnical drug development, particularly with regard to the enhancement of current treatments for tissue inflammation. To cite only one recent example, Mitchison and his postdoc, the Taiwanese scientist Weng Jui-Hsia, have solved what he calls the “colchicine problem” by successfully binding clinically-tested medicinal properties of the ancient poison to a microtubular protein. The impact on cardiovascular medicine—including preventative and pre-surgery treatments for high cholesterol and heart disease patients—has been significant. In 2011, Mitchison helped found the Systems Pharmacology initiative at Harvard which pursues similarly innovative approaches joining the design and testing of innovative drug therapies to challenging demands currently faced by patients, doctors, and biotechnology companies throughout the world.
In 1997, Mitchison was elected to the Royal Society (UK) for “substantial contributions to the improvement of natural knowledge”. In 2008, the American Academy of Arts and Sciences conferred upon him a life membership. He is also a past president of the American Society for Cell Biology, which body awarded him the Keith R. Porter Lectureship in 2013, and was elected by his peers to the National Academy of Sciences of the United States of America in 2014.
Individual achievements apart, few scientists possess Professor Mitchison’s distinguished family pedigree. He descends directly from British life-science pioneers and other original thinkers, including his great grandfather John Scott Haldane (inventor of the respirator) and his grandmother, Naomi Mitchison, the prolific Scots novelist, poet, and activist who first taught him the pleasures of digging in the garden as a boy. Mitchison’s father, the eminent immunologist Avrion Mitchison, always modelled the love of lab work, near at hand, including, during an exercise on the cellular production of antibodies, having asked his son to go and personally extract the necessary cells from the goat in the garden!
Looking back, Mitchison is thoughtful: for him, his family’s greatness did not lie exclusively in the well-earned esteem of others, but also in their clear-sighted and unflinching regard for the object in view, when working with one’s hands, including the craftsperson’s approach to his or her task. Today they remain a family which has learned by doing. And, of course, none of them should ever have toiled alone.
Professor Mitchison is deeply committed to international collaboration and is a firm believer in the value of combining research with education in smaller universities. In recent years, he has been a scientific adviser for on-going research on polysaccharides and novel drug delivery at the HKBU School of Chinese Medicine. Mitchison is deeply interested in how the properties of traditional Chinese medicines may be bound to motor proteins operating within microtubular environments. Mindful of HKBU’s new Chinese medicine hospital to come, Mitchison looks forward to advising HKBU colleagues about how to ensure that the clinical pharmacology of Chinese medicines attains the highest global standards, including lab-based measurement, testing, and blind-trialling. “There are lessons to be learned,” Professor Mitchison opines. In the spirit of his pure science, openness, and his love for Hong Kong, I imagine him presently rolling up his sleeves and setting to work with his hands in the laboratory after hours.