Magdalena Bezanilla

Assistant Professor of Biology, University of Massachusetts

M. Bezanilla Biology Web Site

Ph.D.: Johns Hopkins School of Medicine
Postdoctoral Training: Washington University at St. Louis

Research Interests

Molecular Mechanisms Behind Plant Cell Growth
How cells grow, one of the most fundamental aspects of biology, remains an open question. My research program focuses on plant cells, which unlike many other eukaryotic cells, are not motile. Confined by a relatively rigid cell wall, plant cells take a wide variety of shapes within tissues of the entire plant and ultimately these shapes dictate organismal patterning. Key to plant development is the underlying architecture of individual cells, which at the molecular level is controlled by proteins of the cytoskeleton. The plant cytoskeleton consists of two filamentous networks, microtubules and actin, and their associated proteins.

The actin cytoskeleton is required for a highly polarized form of growth in plant cells known as tip growth. Tip growth, although restricted to a few cell types in most plants, is essential for development in plant species ranging from algae to flowering plants. In seed plants, tip-growing pollen tubes are required for fertilization and thus propagation of the species. Root hairs are another tip-growing cell, important for absorption of water and minerals required for growth and development of the entire plant. The research in my lab focuses on understanding the molecular mechanisms underlying tip growth. These mechanisms bear upon cell development in an evolutionarily wide range of plants.

My lab has pioneered the use of an emerging model system, the moss Physcomitrella patens, to study tip growth. The ease of molecular genetic manipulation, including gene-targeting capabilities, and the abundance of tip growing cells make moss ideal for these studies. Our studies in P. patens to date have uncovered key players required for proper actin dynamics and organization. However, many outstanding questions remain. For example, the molecular events that establish the site of polarization at the cell apex are unknown. Importantly the link between actin dynamics and exocytosis, that is cell growth, remains elusive. Current studies in the lab aim to address these fundamental questions.

Representative publications:

van Gisbergen, P.A.C., Li, M., Wu, S-Z., and Bezanilla, M. 2012. Class II formin targeting to the cell cortex by binding PI(3,5)P2 is essential for polarized growth. The Journal of Cell Biology, 198: 235-250.

Bao, Y., Hu, G., Flagel, L.E. Salmon, A., Bezanilla, M., Paterson, A.H., Wang, Z., Wendel, J.F. 2011. Parallel up-regulation of the profilin gene family following independent domestication of diploid and allopolyploid cotton (Gossypium). PNAS, 108: 21152–21157.

Augustine RC, Pattavina KA, Tuzel E, Vidali L, and Bezanilla M. (2011) Actin Interacting Protein 1 and Actin Depolymerizing Factor Drive Rapid Actin Dynamics in Physcomitrella patens. The Plant Cell, 23: 3696-3710.

Wu S, Ritchie JA, Pan A, Quatrano RS, and Bezanilla M. (2011) Myosin VIII Regulates Protonemal Patterning and Developmental Timing in the Moss Physcomitrella patens. Molecular Plant 4: 909-921.

Vidali L, Burkart GM, Augustine RC, Kerdavid E, Tuzel E, and Bezanilla M. (2010) Myosin XI is Essential for Tip Growth in Physcomitrella patens. The Plant Cell, 22: 1868-1882.

Vidali L, Augustine RC, Fay SN, Franco P, Pattavina KA, and Bezanilla M. (2009) Rapid screening for temperature sensitive alleles in plants. Plant Physiology 151(2): 506-514.

Vidali L, vanGisbergen PAC, Guerin C, Franco P, Li M, Burkart GM, Augustine RC, Blanchoin L, and Bezanilla M. (2009) Rapid formin-mediated actin-filament elongation is essential for polarized plant cell growth. PNAS 106: 13341-6. Epub 2009 Jul 24.

Vidali L, Rounds C, Hepler PK, and Bezanilla M. (2009) LifeAct-mEGFP reveals a dynamic apical F-actin network in tip growing plant cells. PLoS one 4: e5744.

Augustine RC, Vidali L, Kleinman KP, and Bezanilla M. (2008) Actin Depolymerizing Factor is Essential for Viability in Plants and Its Phosphoregulation is Important for Tip Growth. The Plant Journal 54: 863-875.

Vidali L, Augustine RC, Kleinman KP, and Bezanilla M. (2007) Profilin is essential for polarized growth in the moss Physcomitrella patens. The Plant Cell 19: 3705-3722.

Bezanilla, M. , Perroud, P-F, Pan, A., Klueh, P., and Quatrano, R.S. 2005. An RNAi System in Physcomitrella patens with an Internal Marker for Silencing Allows for Rapid Identification of Loss of Function Phenotypes. Plant Biology, 7 : 251-257.

Bezanilla, M. , Pan, A., and Quatrano, R.S. 2003. RNAi in the moss Physcomitrella patens. Plant Physiology, 133 : 470-474.

Bezanilla, M. , Horton, A.C., Sevener H.M., and Quatrano, R.S. 2003. Phylogenetic Analysis of New Plant Myosin Sequences. Journal of Molecular Evolution, 57 : 229-239.

Lee, W.L., Bezanilla, M. , and Pollard, T.D. 2000. Fission Yeast Myosin-I, Myo1p, Stimulates Actin Assembly by Arp2/3 Complex and Shares Functions with WASp. Journal of Cell Biology, 151 (4): 789-799.

Bezanilla, M. , Wilson, J., and Pollard, T.D. 2000. Myosin-II Isoforms in Fission Yeast Assemble into the Contractile Rings at Distinct Times During Mitosis. Current Biology , 10 (7): 397-400.

Bezanilla, M. , and Pollard, T.D. 2000. Myosin-II Tails Confer Unique Functions in S. pombe : Characterization of a Novel Myosin-II Tail. Molecular Biology of the Cell , 11 : 79-91.