In this review our knowledge of ATP binding cassette (ABC) transporters spe
cific for peptides is discussed. Besides serving a role in nutrition of the
cell, the systems participate in various signaling processes that allow (m
icro)organisms to monitor the local environment. In bacteria, these include
regulation of gene expression, competence development, sporulation, DNA tr
ansfer by conjugation, chemotaxis, and virulence development, and the role
of ABC transporters in each of these processes is discussed. Particular att
ention is paid to the specificity determinants of peptide receptors and tra
nsporters in relation to their structure and to the mechanisms of peptide b
inding. (C) 2001 Editions scientifiques et medicales Elsevier SAS.