A Cell's Postal Code Ensures Delivery

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The body’s bone marrow creates a variety of cells which enter the blood stream for delivery to our many organs. As these cells travel through our veins and arteries, they carry their own three letter postal code which ensures delivery to the target organ. For example, when cancer cells spread from the prostate, they always migrate to the bone.

Scientists are now making significant progress in their efforts to find these zip or postal codes which ensure that cells get delivered to the appropriate destination. It’s been found that a particular type of cell (say, a prostate, fat or skin cell), attaches itself to a matching blood vessel receptor on the appropriate organ. Cells with codes that don’t match continue on in the blood stream, until they find the organ that matches their code.

The postal codes are short strings of some of the amino acid units which make up the body’s proteins. The letters stand for three of the twenty types of amino acid building blocks. The three letter sequence must find matching receptors on the blood vessel walls of the corresponding organ.

Eventually researchers hope to compile a library of codes for every organ. Then they can use this information to direct drugs to the organs that need them.

So next time you address a letter, remember that cells used postal or zip codes long before the post office.