Function
The physiologic function of ABC transporters is not well known, and they are expressed constitutively in more than just cancer cells. It is known that ABC transporters bind ATP and use the energy from ATP hydrolysis to drive the transport of various molecules across the plasma membrane as well as intracellular membranes of the endoplasmic reticulum, peroxisome, and mitochondria. ABC transporters are thought to participate in the absorption and secretion of endogenous and exogenous substances. There are normal ABC transporter cells found in digestive cells of the small intestine, large intestine, liver, and pancreas. They are also found in epithelial cells of the kidneys, adrenals, brain, and testes as well as endothelial cells found in the lining of blood vessels and lymphatic vessels. They can be thought of as a hydrophobic vacuum cleaner powered by ATP that expels nonpolar compounds from the lipid bilayer to the exterior.
Read more about this topic: ATP-binding Cassette Family
Famous quotes containing the word function:
“Think of the tools in a tool-box: there is a hammer, pliers, a saw, a screwdriver, a rule, a glue-pot, nails and screws.—The function of words are as diverse as the functions of these objects.”
—Ludwig Wittgenstein (1889–1951)
“The information links are like nerves that pervade and help to animate the human organism. The sensors and monitors are analogous to the human senses that put us in touch with the world. Data bases correspond to memory; the information processors perform the function of human reasoning and comprehension. Once the postmodern infrastructure is reasonably integrated, it will greatly exceed human intelligence in reach, acuity, capacity, and precision.”
—Albert Borgman, U.S. educator, author. Crossing the Postmodern Divide, ch. 4, University of Chicago Press (1992)
“As a medium of exchange,... worrying regulates intimacy, and it is often an appropriate response to ordinary demands that begin to feel excessive. But from a modernized Freudian view, worrying—as a reflex response to demand—never puts the self or the objects of its interest into question, and that is precisely its function in psychic life. It domesticates self-doubt.”
—Adam Phillips, British child psychoanalyst. “Worrying and Its Discontents,” in On Kissing, Tickling, and Being Bored, p. 58, Harvard University Press (1993)