#microvilli

Ready for T

Under attack, our immune system’s T cells prepare to receive an antigen – a chemical fingerprint they’ll use to recognise a pathogen – so they have to be ready. Using expansion microscopy to swell tiny biological details, here scientists capture the T-cell’s microvilli – tiny hair-like structures bristling out from the T-cells’ membranes (shown here in cross-section). Researchers believe the microvilli brush against the antigen, helping to activate a T-cell and awaken the immune response. Molecules moving into and out of the microvilli’s tips, (highlighted in purple, green and yellow) may help to prepare the T-cell for receiving the antigen. Understanding these early steps help scientists discover how some pathogens avoid discovery, or develop new therapies to help those with weakened immune systems.

Written by John Ankers

Image adapted from work by Yunmin Jung and colleagues

Center for Autoimmunity and Inflammation, and Center for Cancer Immunotherapy, La Jolla Institute for Immunology, La Jolla, CA, USA

Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)

Published in Nature Communications, June 2021

HKUST scientists reveal similarities between gut microvilli and inner ear hair cell

Brush border microvilli are microscopic cellular membrane protrusions that increase the surface area of cells and carry out a wide variety of functions, including absorption, secretion and cellular adhesion. Stereocilia, on the other hand, are mechanosensing organelles of hair cells, which respond to fluid motion in numerous types of animals for various functions, including hearing and balance. The two structures are located in separate parts of the human body and perform vastly different functions, despite the very-similar looks and features they have.

The similarities between the two, in fact, are far more than just looks. Mechanistically, the two resembles one another just as closely.

HKUST structural biologist Mingjie Zhang and his team have found that the microvilli and the stereocilia tip-link complexes, despite only having Harmonin in common, are formed via strikingly similar interaction modes. Their findings were published in the January 25, 2016 issue of the journal Developmental Cell.