What is Intraflagellar Transport?

Intraflagellar Transport or IFT is a cellular mechanism that allows cells to ship molecular cargo up and down the length of the cilia.

But first of all let's see what is the structure and function of cilia.
Cilia are slender, microscopic, hair-like structures or organelles that extend from the surface of nearly all mammalian cells (multiple or single). They are primordial.

The length of a single cilium is 1-10 micrometres and width is less than 1 micrometre. Cilia are broadly divided into two types. They function separately and sometimes together:

☛ Motile (or moving) cilia are found in the lungs, respiratory tract and middle ear. These cilia have a rhythmic waving or beating motion. They work, for instance, to keep the airways clear of mucus and dirt, allowing us to breathe easily and without irritation. They also help propel sperm.

☛ Non-motile or primary cilia were long thought to be evolutionary vestigial organs.They are now recognized as playing crucial roles in a number of organs. Some act as a sensory antenna for the cell, receiving signals from other cells or fluids nearby.

In the kidney, for example, cilia bend with urine flow and send a signal to alert the cells that there is a flow of urine.
In the eye, non-motile cilia are found inside the light-sensitive cells (photoreceptors) of the retina. These cilia act like microscopic train-tracks, and allow the transport of vital molecules from one end of the photoreceptor to the other.

For years, scientists have understood that cells send IFT trains up and down paired protein tubes – called microtubule doublets – that act as a skeleton within the cilia. However, they did not know how the transportation system could operate so quickly – and without the trains colliding.

Reference:http://www.aaas.org/news/science-artist-wins-medical-illustrators-award

Read & Learn:http://jcs.biologists.org/content/123/4/499
http://www.ciliopathyalliance.org/cilia/structure-and-function-of-cilia.html

Illustrations by Chris Bickel, senior scientific illustrator at AAAS, who won the Award of Merit in the editorial category for his cover illustration “Miniature Railroad” .Gif: Electron tomography of respiratory cilia by Amelia ShoemarkCorina Marinescu