Elena Shpak, PhD
Department of Biochemistry and Cellular and Molecular Biology
I am interested in the cellular mechanisms of growth and development in plants. How the various specialized cell types arise from just one cell, and how these cells interact with one another in complex ways to coordinate growth have always seemed to me to be some of the most fascinating questions in biology.
One of our laboratory projects is targeted at understanding how plant organ primordia develop. Plant organ primordia are formed by the continual activity of apical meristems. While the meristem determines the size, number and identity of primordia, later processes in the primordia define the final shape and size of organs. Using Arabidopsis pedicels as a model, we are trying to answer the following questions: How is inter- and intra-layer cell growth coordinated? Is there a cell layer which leads the growth or is the growth coordinated by availability of a common mitogen? What is the connection between regulation of cell size and cell proliferation?
We are also studying ERECTA-mediated signaling, a pathway that determines size and shape of aboveground plant organs. ERECTA is a receptor-like kinase (RLK) with an extracellular leucine-rich repeat domain, a single transmembrane domain, and a cytoplasmic Ser/Thr kinase domain. Two functional paralogs of ERECTA, ERL1 and ERL2, are redundant with ERECTA in part of the signaling pathway. Loss of the entire ERECTA family in Arabidopsis leads to dwarfism, a decrease in lateral organ size, abnormal flower development and changes in stomatal patterning. The ERECTA pathway research focuses on identification of downstream components, the mechanism of receptor function, and control of the signaling pathway through the availability and amount of ERECTA protein.
A wide variety of methods are used in the lab, from whole plant morphology and cell biology to molecular biology, genetics, and biochemistry.
Shpak ED, McAbee JM, Pillitteri LJ and Torii KU (2005) Stomatal patterning and differentiation by synergistic interactions of receptor kinases. Science 309(5732): 290-293.
Shpak ED, Berthiaume CT, Hill EJ and Torii KU (2004) Synergistic interaction of three ERECTA-family receptor-like kinases controls Arabidopsis organ growth and flower development by promoting cell proliferation. Development131(7): 1491-1501.
Shpak ED, Lakeman MB and Torii KU (2003) Dominant-negative receptor uncovers modes of action and redundancy in the Arabidopsis ERECTA LRR-RLK signaling pathway that regulates organ shape. Plant Cell 15: 1095-1110.
Torii KU, Hanson LA, Josefsson CAB and Shpak ED (2003) Regulation of inflorescence architecture and organ shape by the ERECTA gene in Arabidopsis. In: Morphogenesis and Patterning in Biological Systems(ed. T. Sekimura). pp. 153-164.