This month's winning image was submitted by Mario Gimona (Austrian Academy of Sciences (mgimona@imb.oeaw.ac.at)). It shows a rat smooth-muscle cell that has been transfected with green fluorescent protein (GFP)-tagged α-actinin and stained for vinculin and filamentous actin.

The actin cytoskeleton was stained with Alexa 568-conjugated phalloidin (red); green fluorescence represents transfected GFP–α-actinin; and blue fluorescence represents vinculin immunostaining. The image was acquired using a fluorescence microscope (Axioskop, Zeiss). Bar, 20 μm.

We are pleased to acknowledge the help of our two external advisors, Ariel Ruiz i Altaba (Developmental Genetics Program, New York Medical Center) and Lelio Orci (Department of Morphology, University Medical Center, Geneva).

To see more Cell of the Month winners, please visit our Cell of the Month archive .