Tuesday, November 01, 2005

A Protein Complex; The Overused Abbreviation

Every subject has it's lingo and it's share of strange terms. Add abbreviations and acronyms, and certain areas of expertise can be almost incomprehensible. Then there is Biology.

Life has a diversification machine, evolution. Thus those who study life (i.e. Biologists) have lots of proteins and genes to name and to investigate. Humans have about 23,000 to 30,000 conventional genes, and many other non-conventional genetic elements such as small RNAs. On top of that these same 23,000+ genes are also found in other vertebrates and many are found in almost every eukaryotic cell. Thus the same molecular machinery in yeast may be completely renamed in humans ... and named weirdly in fruit flies (Drosophila). All this leads to a mass confusion for those that read the biology literature.

But the part that really annoys and frustrates some Biologists is the overused abbreviation - a single abbreviation that is used for several different biological components. The most famous overused abbreviation (as far as I can tell) is APC.

What is APC? Well one thing it doesn't normally stand for is "A Protein Complex".

Ask a cancer biologist, and APC stands for Adenopolyposis Coli, a gene that causes colon polyps. The product of this gene affects several cellular signals and helps organize the cell's cytoskeleton. APC is also mutated in 50-60% of spontaneous colorectal cancers.

Ask a biologist studying the cell cycle what APC stands for, and he will tell you that it stands for the Anaphase Promoting Complex. This molecular machine is responsible for tagetting the destruction of key components so that the cell can proceed along the cell division cycle.

Ask an immunologist what APC stands for, and she may state that it stands for the Antigen Presenting Cell. These cell are exposing foreign antigens to the appropriate white blood cell in order to activate an immunological response.

One abbreviation, three completely different biological items. Enter "APC" into PubMed and ... good luck.

Then one day it was reported that APC (adenopolyposis coli) interacted with the machinery that yanked the chromosomes apart during cell division. This machine is called the kinetochore (greek for moving body). Of course many components of the kinetochores also activate the other APC (the Anaphase Promoting Complex). Activated APC (Anaphase Promoting Complex) destroys the links between duplicated chromosomes so that the act of chromosome separation (i.e. ANAPHASE) can take place. In addition, the first APC (adenopolyposis coli) plays a role in how the cytoskeleton reorganizes during "polarization events". An example of a "polarization event" is when a white blood cell polarizes towards an APC (Antigen Presenting Cells). Some researchers have identified specific versions of APC (adenopolyposis coli) in certain immune cells (perhaps even in APCs!) ... are you confused yet?

The Tower of Babel was built and all those that spoke the same language could no longer communicate.