A look at work from the labs of
CUMC’s graduate program
2007 Harold Weintraub
Graduate Student Awardee
By Ronald K. Liem, Ph.D.
Professor of Pathology & Cell Biology
The Harold Weintraub Graduate Student Award, given annually to 12 to 15 students from around the world, recognizes outstanding achievement during graduate studies in the biological sciences. Six graduate students from Columbia University have received the Weintraub Award over the past four years. This number is matched only by Harvard and is a strong statement of the excellence of the graduate students in the biological and biomedical sciences at Columbia. All six students have done their research in laboratories at the medical center campus and represent a variety of graduate programs.
In 2007, Columbia had two awardees, including Ellen Ezratty, a graduate student in the cell biology and pathobiology program who graduated with distinction in 2007 after completing her research in Dr. Gregg Gundersen’s laboratory.
with Gregg Gundersen
The other Columbia awardee is Michael Crickmore, a student in the biological sciences program, who is finishing his dissertation in the laboratory of Dr. Richard Mann.
Ellen Ezratty grew up in a small town in Pennsylvania and did her undergraduate work at Pennsylvania State University, where she majored in microbiology. As an undergraduate, her main research experiences were during internships at pharmaceutical companies. After graduation, she wanted additional research experience and applied for positions in the pharma industry. She worked for more than a year at a small pharmaceutical company, studying cellular mechanisms of G-protein coupled receptor signal transduction.
To try research in an academic environment, she took a position as a research technician at Memorial Sloan-Kettering Cancer Center. There she utilized embryonic stem cell technology to generate a knock-in mouse model of a gene family involved in angiogenesis and embryonic development. These research experiences convinced her that she wanted to do graduate studies in cell biology. She was particularly interested in Gregg Gundersen’s work on cell migration and wound healing and decided to attend Columbia in the anatomy & cell biology graduate program, a program that has since merged with the pathobiology program. After doing her rotations, she joined the Gundersen laboratory for her thesis work.
For her dissertation, Ellen studied the regulation of microtubule-induced focal adhesion disassembly. She addressed how directed cell migration occurs. During migration, cells form transient attachments to the extracellular matrix through integrin containing plaques called focal adhesions. These focal adhesions establish a connection between the extracellular matrix on the outside of the cell and the cytoskeleton on the inside of the cell and serve as points of traction for the cell. Ellen studied focal adhesion disassembly and formation and the role that the microtubules play in these processes.
To dissect the molecular mechanisms that regulate microtubule-induced focal adhesion disassembly, she developed a model system that kinetically separates the process of focal adhesion disassembly from focal adhesion formation. Ellen identified multiple downstream effectors of focal adhesion disassembly, none of which are involved in the process of focal adhesion formation. In particular, Ellen discovered that components of the endocytic pathways, the process by which cells internalize substances, are important players in focal adhesion disassembly.
This work has important implications for understanding the regulation of integrin signaling, cytoskeletal crosstalk, and endocytosis during cell migration. These studies may aid in our understanding of normal cell migration, which is an integral part of development, as well as abnormal cell motility, which occurs in pathological conditions such as cancer metastasis.
Ellen’s abstract was selected for a minisymposium talk at the American Society for Cell Biology meeting in 2003 and she was invited to present her work in an oral presentation at the Keystone Cell Migration Symposium in 2005. Her presentation received considerable attention and prompted a prominent cell biologist in attendance to write a preview article, which accompanied Ellen’s paper when it was published in Nature Cell Biology.
Recipients of the Weintraub Award present their work at a two-day symposium at the Fred Hutchinson Cancer Center in Seattle, where the late Harold Weintraub was a member of the Basic Science Division until his death in 1995 from cancer at the age of 49. Dr. Weintraub made major contributions to understanding the complexity of mammalian development, including the introduction of anti-sense RNA to elicit mutant phenotypes, and the identification of a gene that can elicit the entire program of muscle differentiation when introduced into a non-muscle cell.
At the Weintraub Award Symposium in 2007, each awardee gave a 30-minute presentation to the graduate students and faculty at the Fred Hutchinson Cancer Center. The diverse topics presented, combined with awareness of Dr. Weintraub’s contributions, left a strong impression on the students who participated.
Ellen — now Dr. Ezratty — started her postdoctoral studies in the lab of Dr. Elaine Fuchs, a Howard Hughes Medical Institute investigator at Rockefeller University, in September. She received a Rockefeller University Women in Science Fellowship for her first year and will pursue other fellowships. In Dr. Fuchs’ laboratory, Dr. Ezratty studies follicle stem cells that reside in a specialized niche called the “bulge,” hoping the studies will lead to a distinguished academic research career.