An "inordinate fondness for transporters" explained?
An often-asked question is, Why are there so many different transporters in a cell to take up a particular substrate? At least part of the answer comes from work on the possible competitive advantage of dual-transporter systems. In such systems, low-affinity transporters function when a nutrient is plentiful in the environment, and the abundance of high-affinity transporters is increased when that nutrient becomes scarce. A dual-transporter system enabled a long "preparation phase" to occur during which cells induce gene expression as they become increasingly starved. Surprisingly, the preparation phase is important not for growth under low-nutrient conditions but rather for fluctuating nutrient amounts as commonly occurs in nature. Thus, this creative study provides a previously unconsidered explanation for the abundance of dual-transporter systems in biology.
Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA. eide@nutrisci.wisc.edu
David J
DJ
Eide
D000818:Animals; D001692:Biological Transport / Q000502:physiology*; D002352:Carrier Proteins / Q000502:physiology*; D006801:Humans
D002352:Carrier Proteins