We have given names to nearly all the different protein molecules that mediate communication between human cells. Now, the audacious goal of contemporary cell biology is to understand how the billion proteins in an average cell allow them to move, multiply, create a brain or defend us against viruses and bacteria. Imaging where and when proteins interact with each other has a major role to play at this frontier. Recent imaging of just a few types of proteins has already led to important new concepts in how immune cells communicate with each other and how they recognise signs of disease. Images of immune cells contacting other cells have revealed temporary membrane structures, often called immune synapses, similar to the synapses that nerve cells make with one another for communication. Exploring how such changing arrangements of proteins occur and how they control immune cell communication is the new science opened up by the immune synapse concept.
My research team and others have also very recently observed that long tubes, made of cell membrane, readily form between immune cells. We called these connections membrane nanotubes and they could constitute a new mechanism for communication between cells that are far apart. A cost, however, is that viruses such as HIV may use these connections to efficiently spread between cells. Thus, we aim to determine how these connections form and what functional consequences they have for the human immune system. We have also observed that RNA can traffic between cells suggesting a new and unexpected mechanism by which cells interact with each other. Specifically, we have found that immune cells can deliver small RNAs into cancer cells to stop them multiplying. Excitingly, high-resolution microscopy of immune cell interactions is still a very young field and more surprises are surely in store.