Benjamin Glick, PhD

Associate Professor, Department of Molecular
Genetics and Cell Biology

Committees on Genetics and Cell Physiology

BA      Neuroscience/Mathematics, 
           Amherst College

PhD     Biochemistry, Stanford University 

Research Summary

Our main goal is to understand the processes that generate Golgi stacks. The cisternal maturation model provides a conceptual framework for studying Golgi formation. This model postulates that new Golgi elements arise at transitional ER (tER) sites, which are specialized for the production of ER-to-Golgi transport vesicles. We have obtained evidence that in budding yeasts, Golgi distribution is a consequence of tER organization. In Saccharomyces cerevisiae, Golgi cisternae are dispersed throughout the cytoplasm and the entire ER network functions as tER, whereas in Pichia pastoris, ordered Golgi stacks are located next to discrete tER sites. We are analyzing these two yeasts in parallel with vertebrate cells. Our specific approaches are: (1) To characterize S. cerevisiae mutants with defects in premitotic Golgi inheritance. We isolated S. cerevisiae mutants that fail to partition Golgi elements into small buds, and are now studying the corresponding genes. (2) To characterize tER organization and biogenesis in P. pastoris through a combination of genetics, molecular biology, video microscopy and computer simulations. P. pastoris is an ideal model organism for these studies. For example, we have labeled the P. pastoris tER with a GFP fusion protein, and are using the resulting strain to identify mutants with altered tER structures. (3) To explore tER organization and dynamics in vertebrate cells. A single vertebrate cell contains several hundred structures that resemble the tER sites present in P. pastoris. Therefore, we are exploring the dynamics and molecular components of vertebrate tER sites. These experiments are revealing evolutionarily conserved mechanisms of tER organization. 

A second project in the lab involves optimizing the red fluorescent protein DsRed. Like its more famous cousin GFP (green fluorescent protein), DsRed potentially has wide application as a reporter and fusion protein tag. However, wild-type DsRed suffers from several drawbacks that limit its usefulness. For example, wild-type DsRed matures very slowly, requiring more than 24 hours at 37°C to achieve maximal fluorescence. We overcame this problem by using directed evolution to create rapidly maturing DsRed variants. One such variant is now marketed commercially as DsRed-Express. Ongoing work is aimed at generating DsRed variants that will be as versatile as GFP. 

Some Selected Papers

Glick, B. S. (2002). "Can the Golgi form de novo?" Nat Rev Mol Cell Biol 3: 615-9. PubMed Citation Article 

 Bevis, B. J. and Glick, B. S. (2002). "Rapidly maturing variants of the Discosoma red fluorescent protein,(DsRed)." Nat Biotechnol 20: 83-7. PubMed Citation  Article

Bevis, B. J., Hammond, A. T., Reinke, C. A. and Glick, B. S. (2002). "De novo formation of transitional ER sites and Golgi structures in Pichia pastoris." Nat Cell Biol 4: 750-6. PubMed Citation  Article

Soderholm, J., Bevis, B. J. and Glick, B. S. (2001). "Vector for pop-in/pop-out gene replacement in Pichia pastoris." Biotechniques 31: 306-10, 312. PubMed Citation

Rossanese, O. W., Reinke, C. A., Bevis, B. J., Hammond, A. T., Sears, I. B., O'Connor, J. and Glick, B.S. (2001). "A role for actin, Cdc1p, and Myo2p in the inheritance of late Golgi elements in Saccharomyces cerevisiae." J Cell Biol 153: 47-62. PubMed Citation

Hammond, A. T. and Glick, B. S. (2000). "Dynamics of transitional endoplasmic reticulum sites in vertebrate cells." Mol Biol Cell 11: 3013-30. PubMed Citation Article

Hammond, A. T. and Glick, B. S. (2000). "Raising the speed limits for 4D fluorescence microscopy."  Traffic 1: 935-40. PubMed Citation Article

Rossanese, O. W., Soderholm, J., Bevis, B. J., Sears, I. B., O'Connor, J., Williamson, E. K. and Glick, B.S. (1999). "Golgi structure correlates with transitional endoplasmic reticulum organization in Pichia pastoris and Saccharomyces cerevisiae." J Cell Biol 145: 69-81. PubMed Citation

Updated 10/18/05.