The glycerol facilitator GlpF, its aquaporin family of channels, and their selectivity

Abstract

Publisher Summary The “glycerol facilitator” GlpF, a highly selective transmembrane channel that conducts glycerol and certain other small uncharged organic molecules, was the first member of the large aquaporin family (AQP family) to be identified at the genetic level and functionally characterized. Once glycerol is passaged inside the cell, it is rapidly phosphorylated by glycerol kinase to produce glycerol 3-phosphate that proceeds by dehydrogenation to dihydroxyacetone phosphate (DHAP) or to phospholipid synthesis where glycerol provides the basis for attachment of fatty acid chains and phophatidyl head groups in ∼2/3 of cellular phospholipids. The glp regulon is inducible by glycerol 3-phosphate which provides an advantage for growth of Escherichia coli on glycerol. The glpF gene is the first gene on the glp operon that also contains the gene for glycerol kinase.