The Bhabha lab will explore how the single-celled parasites microsporidia deploys a unique mechanism to impale and invade animal cells. Microsporidia attack a wide range of hosts, from insects to humans, and are responsible for everything from opportunistic infections in people with HIV to colony collapse in honey bees. To infect other cells, microsporidia shoot out a harpoon-like protein-based machine called a polar tube that anchors them to their cellular target. Once attached, this apparatus serves as a conduit through which the infectious spore enters its host. Combining an array of recently developed cutting-edge techniques in electron microscopy, X-ray crystallography, and structural biology, our group will determine how microsporidia unfurl this polar tube, which—in less than half a second—springs from its resting state, coiled inside the parasite, to its fully extended conformation. We will isolate the proteins that are part of this dynamic structure, determine how they assemble to form a tube and rearrange when the tube rockets out of the parasite, and identify any additional components that play a role in this dramatic molecular event. Our findings could be used to develop novel methods for the treatment and prevention of microsporidial infections.