Hanson Lab
Dynamic Organization of the Plant Cell

A cultured cell



The ability to label different subcellular locations with the green fluorescent protein (GFP) has made it possible to visualize intracellular activities in living cells. We have introduced chimeric genes which express GFP in a variety of organelles within the plant cell in order to study the dynamics of cell organization.  Labeling plastids with GFP led to the rediscovery of tubules emanating from plastids. (1) Now termed stromules, for stroma-filled tubules, the function and mechanism of formation of these unexpected structures remains a topic for study. (2-4)

Click here to view our web essay on stromules.A cultured cell

Click here to view an article in the Cornell Chronicle about our rediscovery of chloroplast extensions and connections.

We have investigated whether myosins are involved in movement of stromules, plastids, mitochondria, peroxisomes, and other subcellular structures.  Plant genomes encode the myosin XI family of myosin proteins.  We have placed fluorescent labels on portions of the tail regions of Arabidopsis myosin XIs in order to determine whether they localize, and therefore what role a particular myosin may play in movement of different types of organelles. (5-7)

Chloroplasts accumulate at the top of leaf cells, which can improve acquisition of light energy.  In the presence of strong light, chloroplasts move to the side of the cells, possibly resulting in protection from photodamage.  The actin cytoskeleton mediates these responses, but the signal transduction pathway leading to chloroplast movement and the mechanism of chloroplast motility is not entirely understood.  We are exploring the effect that chloroplast movement has on photosynthesis and the role of the cytoskeleton and signaling proteins in chloroplast positioning.   This project is in collaboration with Dr. Tom Owens (Cornell Section of Plant Biology).


1.    Kohler, R. H., Cao, J., Zipfel, W. R., Webb, W. W., and Hanson, M. R. (1997) Exchange of protein molecules through connections between higher plant plastids, Science 276, 2039-2042.

2.    Hanson, M. R., and Sattarzadeh, A. (2008) Dynamic morphology of plastids and stromules in angiosperm plants, Plant, cell & environment 31, 646-657.

3.    Hanson, M. R., and Sattarzadeh, A. (2011) Stromules: recent insights into a long neglected feature of plastid morphology and function, Plant physiology 155, 1486-1492.

4.    Hanson, M. R., and Sattarzadeh, A. (2013) Trafficking sof proteins through plastid stromules, The Plant cell 25, 2774-2782.

5.    Sattarzadeh, A., Krahmer, J., Germain, A. D., and Hanson, M. R. (2009) A myosin XI tail domain homologous to the yeast myosin vacuole-binding domain interacts with plastids and stromules in Nicotiana benthamiana, Molecular plant 2, 1351-1358.

6.    Sattarzadeh, A., Schmelzer, E., and Hanson, M. R. (2011) Analysis of organelle targeting by DIL domains of the Arabidopsis myosin XI family, Frontiers in plant science 2, 72.

7.    Sattarzadeh, A., Schmelzer, E., and Hanson, M. R. (2013) Arabidopsis myosin XI sub-domains homologous to the yeast myo2p organelle inheritance sub-domain target subcellular structures in plant cells, Frontiers in plant science 4, 407.

Project Sponsors

The Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy grant DE-FG02-09ER16070

Maureen R. Hanson
Liberty Hyde Bailey Professor
Phone: 607-254-4833
Fax: 607-255-6249

Hanson Laboratory
Department of Molecular Biology and Genetics
321 Biotechnology Building
Cornell University
Ithaca, NY 14853
Phone: 607-254-4832

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Maureen Hanson at NCBI Pubmed   Maureen Hanson at Google Scholar