RUI: Elucidating Regulatory Mechanisms for Bridging the Contractile Ring with the Cellular Membrane in Fission Yeast Cytokinesis

Grand Valley State University, Allendale MI

Investigators

Abstract

Intellectual Merit. Cell division is a fundamental biological event that underlies the growth and development of all organisms. The broad questions addressed through this research are universal to cell division in all biological systems. How does an individual cell know where to physically separate into two new cells? When is an appropriate time for a cell to divide? Proteins that are essential for physically dividing the cell undergo dynamic rearrangements within the cell to concentrate at the future site of cell division and coalesce into a ring structure called the contractile ring. Physical separation of the mother cell into two identical cells occurs when the contractile ring constricts during cytokinesis. Temporally and spatially organizing such a large assortment of proteins at the cellular division site requires precise regulatory mechanisms. Because fission yeast (Schizosaccharomyces pombe) cells utilize evolutionarily conserved machinery during this process, they are an ideal model system to reveal general cell division properties. In fission yeast, a conserved scaffolding protein called Mid1 is a foundational part of the contractile ring, functioning as the initial organizer to anchor the structure to the cell membrane and to recruit essential cytokinetic proteins to the cell division site. In this project, a research team, consisting primarily of undergraduate students, will investigate the Mid1 scaffolding function at a molecular level. Preliminary results generated by student researchers suggest that Mid1 directly associates with multiple cytokinetic ring proteins and utilizes an enzyme-dependent mechanism to interact with the cell membrane. The research will characterize Mid1 interactions with other cytokinetic proteins and the cell membrane to elucidate a molecular model for bridging the cell division machinery to the cell membrane. Given that Mid1 is functionally similar to anillin, a scaffolding protein required for cytokinesis in animal cells, a detailed study of the Mid1 scaffolding function is at the core of understanding cytokinesis in other biological systems. Broader Impact. Among the greater than 20,000 undergraduate students at Grand Valley State University (GVSU), 41% of incoming freshman are the first in their family to attend college, 15.5% of recent graduates were over the age of 25 years (non-traditional) and the majority of current students are financially contributing to their own education. Like many of the students at GVSU, the principal investigator is a first-generation college graduate herself. A specific objective of this research project is to provide an intellectually meaningful research experience to undergraduate students, primarily first generation students and/or non-traditional students. Student researchers will contribute to the scientific goals related to cell division while receiving a comprehensive training experience. The practical skills gained will include creative problem solving, proper laboratory technique, clear oral and written communication, hypothesis development, and experimental design. Results will be disseminated in peer-reviewed journals, and undergraduate researchers will present their findings at regional and national scientific meetings. Cell and molecular biology majors at GVSU are among the top in the country with consistently high scores on standardized tests in this area. Graduates are making significant scientific contributions in doctoral programs or industrial research positions. The educational goals of this research project will positively impact students who are committed to long-term scientific careers and will further intensify the research atmosphere at GVSU.