I am dissecting the molecular mechanisms employed by diverse sets of proteins which remodel the microtubule and actin cytoskeleton. The precise control of the dynamic equilibrium between polymeric and monomeric cytoskeleton components is a prerequisite for proper cell function, e.g. during migration, polarization or cytokinesis.

For this, I employ biochemical and biophysical methods, and directly visualize protein dynamics during microtubule and actin filament assembly and disassembly in real-time, using multi-color, single-molecule TIRF microscopy. I am particularly interested in mechanisms of the often neglected microtubule-actin filament crosstalk as well as formin function and polymer recycling. My work is supported by the DFG (Germany).

When not in the lab, I spend my time playing basketball, reading flap books or building sand castles.

Publications:

• Fenn S*, Breitsprecher D*, Gerhold CB, Witte G, Faix J, Hopfner KP. Structural biochemistry of nuclear actin-related proteins 4 and 8 reveals their interaction with actin. EMBO J. 2011 Apr 15. *contributed equally
• Breitsprecher D, Kiesewetter AK, Linkner J, Vinzenz M, Stradal TE, Small JV, Curth U, Dickinson RB, Faix J. Molecular mechanism of Ena/VASP-mediated actin-filament elongation. EMBO J. 2011 Feb 2;30(3):456-67.
• Ramalingam N, Zhao H, Breitsprecher D, Lappalainen P, Faix J, Schleicher M. Phospholipids regulate localization and activity of mDia1 formin. Eur J Cell Biol. 2010 Oct;89(10):723-32.
• Breitsprecher D, Faix J. The inverted Formin INF2 sorts it out. Dev Cell. 2010 May 18;18(5):689-90.
• Breitsprecher D, Kiesewetter AK, Linkner J, Faix J. Analysis of actin assembly by in vitro TIRF microscopy. Methods Mol Biol. 2009;571:401-15.
• Filopodia: Complex models for simple rods. Faix J, Breitsprecher D, Stradal TE, Rottner K. Int J Biochem Cell Biol. 2009 Aug-Sep;41(8-9):1656-64. Epub 2009 Feb 23. Review.
• Breitsprecher D, Kiesewetter AK, Linkner J, Urbanke C, Resch GP, Small JV, Faix J. Clustering of VASP actively drives processive, WH2 domain-mediated actin filament elongation. EMBO J. 2008 Nov 19;27(22):2943-54.
• Lai FP, Szczodrak M, Block J, Faix J, Breitsprecher D, Mannherz HG, Stradal TE, Dunn GA, Small JV, Rottner K. Arp2/3 complex interactions and actin network turnover in lamellipodia. EMBO J. 2008 Apr 9;27(7):982-92.

I am interested in the combinatorial effects of disassembly factors on branched actin arrays. I use yeast genetics and in vitro biochemistry to begin to elucidate the emergent properties of several disassembly components working in concert. My work is supported by the American Heart Association.

When I'm not in the lab I'm usually somewhere outdoors: either biking, hiking, skiing or shoveling snow, depending on the season.

Publications:

• Ydenberg, C.A. and M.D. Rose, 2009. Antagonistic regulation of Fus2p nuclear localization by the pheromone pathway and the cell cycle. J Cell Biol 184:409
• Peterson, J.M., C.A. Ydenberg and M.D. Rose, 2008. Dynamic localization of yeast Fus2p to an expanding ring at the cell fusion junction during mating. J Cell Biol 181:697-709.
• Ydenberg, C.A. and M.D. Rose, 2008. Yeast Mating: A Model of Cell and Nuclear Fusion. Meth. Mol. Biol. 475:3-20.

Visit me on Linked-in: http://www.linkedin.com/in/cy1981

APC and formins both are actin nucleators and collaborate to promote the assembly of actin filaments in vitro but the specific functions of this collaboration are still unknown. I am interested in understanding the mechanisms and functions of APC-formin interactions in relation to actin assembly. To address this I employ two complementary approaches: mammalian cell culture techniques and in vitro biochemistry.

Education:
PhD, IIT Bombay, India, 2009

Publications:

• Jaiswal R., Patel, R.Y., Asthana, J., Jindal, B., Balaji, P.V., Panda, D. (2010) E93R substitution of Escherichia coli FtsZ induces bundling of protofilaments, reduces GTPase activity, and impairs bacterial cytokinesis. J. Biol. Chem., 285, 31796-31805.
• Jaiswal, R. and Panda, D. (2009) Differential assembly properties of Escherichia coli FtsZ and Mycobacterium tuberculosis FtsZ: An analysis using divalent calcium. J. Biochem. 146, 733-742.
• Srivastava, R.K., Jaiswal, R., Panda, D., Wangikar, P.P. (2009) Megacell phenotype and its relation to metabolic alterations in transketolase deficient strain of Bacillus pumilus. Biotechnol. Bioeng. 102, 1387-1397.
• Jaiswal, R. and Panda D. (2008) Cysteine-155 residue plays an important in the assembly of Mycobacterium tuberculosis FtsZ. Protein Sci. 17, 846-854.
• Jaiswal, R., Beuria, T.K, Mohan, R., Mahajan, S.K., and Panda, D. (2007) Totarol inhibits bacterial cytokinesis by perturbing the assembly dynamics of FtsZ. Biochemistry 46, 4211-4220.

My research focuses on how cells establish and maintain a polarity axis, which is essential for processes such as cell growth, movement, and division. In particular, I am interested in understanding how the cell polarity factor Bud6 regulates the two yeast formins (Bni1 and Bnr1) to orchestrate the development of a polarized actin cable network. Using a combination of biochemistry, genetics, and fluorescence microscopy allows me to address both the mechanistic details governing Bud6's role in formin-mediated actin assembly, as well as the broader cellular consequences arising from the disruption of interactions among Bud6, formins, and their binding partners.

Education:
BS, Biology; BA, Chemistry. UNC Chapel Hill, 2006.

I am studying the mechanisms through which formin activities are regulated by various other cellular factors. For example, actin filament nucleation and elongation by the budding yeast formin Bnr1p is affected in distinct ways by Bud14p, Smy1p and Hof1p, among other regulators. I am attempting to dissect the mechanistic details of these individual formin-regulatory interactions, and investigating their evolutionary conservation in mammalian formins.

Publications:

• Rational design of memory in eukaryotic cells. Ajo-Franklin CM, Drubin DA, Eskin JA, Gee EP, Landgraf D, Phillips I, Silver PA. Genes Dev. 2007 Sep 15;21(18):2271-6.
• The role of protein arginine methylation in the formation of silent chromatin. Yu MC, Lamming DW, Eskin JA, Sinclair DA, Silver PA. Genes Dev. 2006 Dec 1;20(23):3249-54.

Education:
BA, Physics. Cornell University, 2004.

Previous positions:
Research Associate, FoldRx Pharmaceuticals Inc. (now a subsidiary of Pfizer Inc.)
Lab Manager, Harvard Medical School (Pamela Silver's lab).

Publications:

• cpsf1 is required for definitive HSC survival in zebrafish. Bolli N, Payne EM, Rhodes J, Gjini E, Johnston AB, Guo F, Lee JS, Stewart RA, Kanki JP, Chen AT, Zhou Y, Zon LI, Look AT. Blood. 2011 Apr 14;117(15):3996-4007.
• Zebrafish microRNA-126 determines hematopoietic cell fate through c-Myb. Grabher C, Payne EM, Johnston AB, Bolli N, Lechman E, Dick JE, Kanki JP, Look AT. Leukemia. 2011 Mar;25(3):506-14.
• Expression of the cytoplasmic NPM1 mutant (NPMc+) causes the expansion of hematopoietic cells in zebrafish. Bolli N, Payne EM, Grabher C, Lee JS, Johnston AB, Falini B, Kanki JP, Look AT. Blood. 2010 Apr 22;115(16):3329-40.
• Prosaposin inhibits tumor metastasis via paracrine and endocrine stimulation of stromal p53 and Tsp-1. Kang SY, Halvorsen OJ, Gravdal K, Bhattacharya N, Lee JM, Liu NW, Johnston BT, Johnston AB, Haukaas SA, Aamodt K, Yoo S, Akslen LA, Watnick RS. Proc Natl Acad Sci USA. 2009 Jul 21;106(29):12115-20.

Sasha is an Akita/Bernese Mountain Dog mix who joined the lab at just 10 weeks old in Februrary 2001. She performs multiple essential roles in the lab, such as food disposal and napping. When she is not stretched out in the middle of the lab or supervising the lunchroom, Sasha enjoys chasing squirrels, rolling around in unpleasant-smelling things, being really cute and running daily with Bruce.

Though Kira's hyperactivity prevents her from working in the lab full-time, it is believed that she is working on a secret project for world domination. It is unknown what she might be planning, but many believe that her project involves high intensity light, as Kira is obsessed with chasing lasers.