Lab News

Friend, J.E., Sayyad, W.A., Arasada, R., McCormick, C.D., Heuser, J.E., and Pollard, T.D. (2017) Fission yeast Myo2: Molecular organization and diffusion in the cytoplasm. Cytoskeleton. In press. This paper shows that single Myo2 molecules with two heads and a long tail diffuse in the cytoplasm of interphase and mitotic cells. 
Arasada,R., Sayyad, W.A., Berro, J., and Pollard, T.D. (2017) High-speed super-resolution imaging of the proteins in fission yeast clathrin-mediated endocytic actin patches. Molec. Biol. Cell. In press. This study used FPALM super resolution microscopy with 35 nm spatial resolution and 1 second time resolution to track single protein molecules in fission yeast actin patches. The actin assembles in two zones at sites of clathrin-mediated endocytosis.
Sofia Espinoza defended her thesis on July 17, 2017.
Lab member undergraduate student Frank Chen graduated from Yale College with honors including Phi Beta Kappa and will enter Weill-Cornell Medical School in New York next term.
Alexander Epstein, 2018, is one of three Yale University juniors to be awarded the prestigious Barry Goldwater Scholarship for excellence in science, technology, engineering, and math (STEM) fields and education. These awards are given to sophomores and juniors who also demonstrate a long term commitment to their chosen field of inquiry.
Tom Pollard was elected to a three year term on the Council of the National Academy of Sciences, which will begin this summer. 
Tom Pollard will give the keynote address at the Cold Spring Harbor Laboratory meeting on “Cellular Dynamics and Models” April 12, 2017.
Caroline Laplante and colleagues published their analysis of the structure of cytokinesis nodes by super resolution localization microscopy. The article entitled “Molecular organization of cytokinesis nodes and contractile rings by super-resolution fluorescence microscopy of live fission yeast” appeared in PNAS. See
Sam Dundon joined the laboratory as a postdoctoral associate coming from Amy Gladfelter’s laboratory at Dartmouth College.
Naomi Courtemanche and Qian Chen published a paper in Nature Cell Biology revealing the adverse effects of Lifeact-GFP on actin assembly in vitro and in cells, but found ways to use Lifeact-GFP to make valuable quantitative measurements of polymerized actin in live cells. Two important finding were that the fission yeast contractile ring consists of about 500 µm of actin filaments and these filaments shorten as the ring constricts.
Tom Pollard will receive the Carl Zeiss Award from the German Society for Cell Biology this month.
During the Fall Term of 2015 members of the lab took new independent positions. Naomi Courtemanche is Assistant Professor of Genetics, Cell Biology and Development at the University of Minnesota and Qian Chen is Assistant Professor of Biology at the University of Toledo. Three new postdoctoral associates joined the laboratory: Moon Chatterjee from Inari Kursula’s lab at the University of Hamburg in Germany, Wasim Sayyad from Vincent Torre’s lab at the International School for Advanced Studies in Trieste, Italy, and Sumit Kumar Dey from Siddhartha S Jana’s lab at the Indian Association for the Cultivation of Science in Kolkata India.
Chris Jurgenson (now an assistant professor at Delta State University) has a paper accepted in Acta Crystallogr F Struct Biol Commun entitled “Crystals of Arp2/3 complex in two new space groups with structural information about actin related protein 2 and potential WASP binding sites.”
iBioSeminar just posted the first of Tom Pollard’s four video seminars entitled “Mechanism of cell motility part 1.”
Rajesh Arasada has a paper in press in Journal of Cell Science showing that the F-BAR protein Rga7p is required to deliver ß-glucan synthetase Bgs4p from the late Golgi compartments to the plasma membrane adjacent to the contractile ring.
Tom Pollard will receive the 2015 National Academy of Sciences  Award for Scientific Reviewing – presented in the field of biochemistry. “He is honored for his reviews tracing the history of cell motility from its beginnings, critically analyzing the biochemical reactions responsible for cellular movements, critiquing the methods and assumptions used in the field, and synthesizing the information available into creative models that have guided the development of the field.”
Naomi Courtemanche published a paper in Structure (23:68-79) with a refined model for how formin FH2 domains interact with the barbed end of the actin filament. Naomi contributed biochemical experiments on mutant proteins to test ideas that emerged from molecular dynamics simulations by collaborators in the laboratory of Greg Voth at the University of Chicago.

Naomi Courtemanche published a paper in JBC entitled “Abl2/Abl-related Gene Stabilizes Actin Filaments, Stimulates Actin Branching by Actin-related Protein 2/3 Complex and Promotes Actin Filament Severing by Cofilin.” Naomi collaborated with Stacey Gifford from Tony Koleske’s lab on his favorite protein, the tyrosine kinase Arg, which has some interesting effects on actin assembly.
The Journal of Cell Science accepted Kai-Ming Pu and Matt Akamatsu’s paper entitled “The septation initiation network controls the assembly of nodes containing Cdr2p for cytokinesis in fission yeast.”
The Journal of Biological Chemistry accepted a new paper by Qian Chen and Naomi Courtemanche entitled “Aip1 promotes actin filament severing by cofilin and regulates the constriction of the cytokinetic contractile ring.”
The Biophysical Journal published a special issue on quantitative cell biology including a review by Tom Pollard entitled “The Value of Mechanistic Biophysical Information for Systems Level Understanding of Complex Biological Processes Such as Cytokinesis.”
On September 18th Tom Pollard presented a talk entitled “Models for the dynamics of the cytokinesis machinery across the entire cell cycle in fission yeast” at the Banff International Research Station meeting “Mathematics of the Cell: Integrating Genes, Biochemistry and Mechanics.” Find the talk at:…

Rajesh Arasada has a new paper in Cell Reports on an anchor for the cytokinetic contractile ring. He discovered that Bgs1p, a transmembrane enzyme that synthesizes the septum in the cleavage furrow, is also an anchor for the contractile ring. Bgs1p depends on the F-BAR protein Cdc15p to move to the plasma membrane in a timely fashion. The title of the paper is “Contractile Ring Stability in S. pombe Depends on F-BAR Protein Cdc15p and Bgs1p Transport from the Golgi Complex.”

See the paper in Cell where Tom Pollard explains why scientists should advocate for governmental support of basic research. [pdf]

Qian Chen, Ph.D., publishes: Actin filament severing by cofilin dismantles actin patches and produces mother filaments for new patches. [pdf]

Naomi Courtemanche, Ph.D., publishes: Tension modulates actin filament polymerization mediated by formin and profilin. [pdf]