I think we simply brought forward new data which had been long awaited in the field of plant hormones and plant developmental biology. We were a bit lucky, having been in the right place at the right time with the proper know-how, and we took a chance.

“...the paper was based on a broad international cooperation, and it has been quite valuable to realize how science in general, and biology in particular, can connect people.”

The fact that our paper covers as model objects, not only plants and plant organs, but also in vitro cultured plants, human and yeast cells, gives it a broader scope which may provide an additional reason for a higher citation rate.

The paper provides evidence confirming the transport function for some proteins from the plant PIN protein family which, for a long time, were supposed to be carriers for the plant hormone auxin. However, the data available until then was consistent with two possible functions of PINs: as either auxin carriers themselves or as positive regulators of cellular auxin efflux.

Using a combination of molecular-biological, biochemical, and cytological methods, we have proved that some PIN proteins catalyze specifically the auxin efflux from cells to the extracellular space. They do so, not only in plants, but also in human and yeast cells, in spite of the fact that in both humans and yeasts, neither one possesses an auxin-related signaling system nor does auxin play any role in the regulation of their development.

The significance of our work lies in a detailed characterization of the biochemical function of some members of the family of PIN proteins in plants. These proteins catalyze the transport of the plant hormone auxin across plasma membranes out of cells.

For physical-chemical reasons, these transporters—the "auxin efflux carriers"—are key components of the so-called polar auxin transport (the strictly directional movement of auxin molecules from cell to cell through the plant body). This process forms the crucial part of the regulatory system that helps plants to coordinate their development.

For years, our lab was interested in studies of auxin signaling and mechanism(s) involved in regulation of intracellular auxin levels. Obviously, transport of auxin molecules across a plasma membrane is one of these possible mechanisms.

For a long time, we used plant cell cultures as simplified experimental models for studies of cellular and subcellular processes. We have realized that some high-quality tobacco cell lines with stable phenotype and standard growth cycle may represent very useful models for biochemical studies of auxin transporters, and that these tobacco cell lines are experimental systems complementary to Arabidopsis thaliana, a model plant widely used in the experimental biology of plants.

We have collaborated with our colleagues from other laboratories who either provided us with constructs for transformations or did all the work with human and yeast cells.

Along the way we have faced general problems accompanying the experimental work. Last, but not least, it was very difficult to get the paper published. However, in the end, the very strict referees definitely helped us to improve the manuscript significantly.

The phenomenon of polar auxin transport is unique and is the subject of a very complex regulation. Our lab now concentrates on characterization of mechanism(s) of this regulation on molecular and cellular levels.

I am not sure if there are any specific social and/or political implications for our research. Anyway, the paper was based on a broad international cooperation, and it has been quite valuable to realize how science in general, and biology in particular, can connect people.