Organization of cytoplasm
Previous and Current Research
The Hyman lab has a long and distinguished history studying cell polarity, spindle assembly and positioning, and microtubule dynamics. To learn more about our past research, visit the Key Discoveries page on our website. Currently, the main goal of the lab is to understand how cells form non-membrane bound compartments.
We primarily use C.elegans as a model system, but we complement this with studies in Xenopus extracts and human cells. Our work using genome-wide RNAi screens has shown that rather small numbers of molecular components are required to organize each of these compartments. Using a combination of genetics and physics, we have discovered that a principle underlying the organization of these structures is liquid-liquid phase separation. We study these compartments both in vivo and in vitro, using reconstitution methods.
We complement our studies by taking genomics approaches to cataloguing the proteins required for forming these compartments. We have followed up on our RNAi screens by developing methods to tag proteins in large pieces of genomic DNA, using recombineering. This has allowed us to make genome-wide libraries of tagged proteins for follow up of genes identified by screening.
Phase Separation. We are actively studying the physical mechanisms of phase separation in the lab, using biophysical, genetic, and chemical methods. Using TransgeneOmic BAC cell lines, we can identify proteins that form non-membrane bound compartments in HeLa cells and test which stress-conditions induce their condensation. We also observe this process during development in C. elegans, and use measures of P granule growth rate, size distribution, and mechanical properties to test possible physical models that could underlie this behavior. Additionally, we purify proteins known to form non-membrane bound compartments to assess how these proteins behave under different conditions in vitro and test how they interact with other proteins and RNA.
Centrosomes. Centrosomes are the major sites of microtubule nucleation in dividing cells. How is the pericentriolar matrix (PCM), an amorphous, micrometer-scale structure, assembled from thousands of nanometer-scale proteins in the cytoplasm? And what are the physical properties of this non-membrane bound compartment?
Cell Rounding. Mitotic cell rounding is thought to facilitate proper cell division, but until recently, little has been known about the physical forces driving this process. The Hyman lab studies cell rounding by using Atomic Force Microscopy (AFM). This technique is now being used in the lab to investigate which genes are involved in mitotic cell rounding and why.
Temperature. We are interested in the effect that high and low extremes of temperature have on various aspects of nematode biology, including: cell biology, cell cycle control, development and fitness. We aim to address this question using molecular biology tools, microscopy and genetics in the model organism C. elegansand hope to extend our knowledge by studying other nematodes, namely Caenorhabditis briggsae and Pristionchus pacific us.
Future Projects and Goals
To understand the properties of non-membrane bound compartments and how they relate to disease.
Methodological and Technical Expertise
- BAC recombineering
- Single molecule microscopy
- C.elegans transgenomics
- Protein expression and purification
Patel A, Lee HO, Jawerth L, Maharana S, Jahnel M, Hein MY, Stoynov S, Mahamid J, Saha S, Franzmann TM, Pozniakovski A, Poser I, Maghelli N, Royer LA, Weigert M, Myers EW, Grill S, Drechsel D, Hyman AA, Alberti S.
A Liquid-to-Solid Phase Transition of the ALS Protein FUS Accelerated by Disease Mutation
Cell, 27 August 2015
Woodruff JB, Wueseke O, Viscardi V, Mahamid J, Ochoa SD, Bunkenborg J, Widlund PO, Pozniakovsky A, Zanin E, Bahmanyar S,Zinke A, Hong SH, Decker M, Baumeister W, Andersen JS, Oegema K, Hyman AA.
Centrosomes. Regulated assembly of a supramolecular scaffold in vitro.
Science. 2015 May 15;348(6236):808–12.
Hyman AA, Weber CA, Jülicher F.
Liquid-liquid phase separation in biology.
Annu Rev Cell Dev Biol. 2014 Oct 11;30:39–58.
Stewart MP, Helenius J, Toyoda Y, Ramanathan SP, Muller DJ, Hyman AA.
Hydrostatic pressure and the actomyosin cortex drive mitotic cell rounding.
Nature. 2011 Jan 13;469(7329):226–30.
Brangwynne CP, Eckmann CR, Courson DS, Rybarska A, Hoege C, Gharakhani J, Jülicher F, Hyman AA.
Germline P granules are liquid droplets that localize by controlled dissolution/condensation.
Science. 2009 Jun 26;324(5935):1729–32.