The gut is lined by cells containing brush borders, which are composed of arrays of microvillar protrusions that help in nutrient absorption and provide a barrier against pathogens and toxins. Microbes such as E. coli can destroy microvilli with potentially life-threatening results. But how microvilli form has not been well understood.
Using super-resolution microscopy and live cell imaging, Matthew Tyska, PhD, and colleagues show that a protein called insulin receptor tyrosine kinase substrate (IRTKS) promotes microvilli elongation. They previously discovered that IRTKS is the only protein in the intestinal brush border containing an I-BAR domain. I-BAR proteins help form membrane protrusions.