Table 1.

Overview of selected factors modulating the gene and/or protein expression and function of the intestinal peptide transporter PEPT1

Modulator	Effect on PEPT1	Kind of modulation	References
Amino acids leucine and phenylalanine	Control of pept1 promoter activity via the AARE in rats	Transcriptional	Shiraga et al. (2006a)
Transcription factor SP1	Binds to the PEPT1 promoter and modulates the basal pept1 transcription	Transcriptional	Shimakura et al. (1998)
Transcription factor Cdx2	Modulates pept1 transcription in concert with SP1 and with butyrate in mammals	Transcriptional	Shimakura et al. (2005b) Dalmasso et al. (2002)
Transcription factor DAF-16	Represses pept1 transcription in Caenorhabditis elegans	Transcriptional	Meissner et al. (2012)
Peptidase inhibitors amastatin and bestatin	Decrease intracellular peptide hydrolysis and reduce pept1 function in C. elegans	Functional	Benner et al. (1973)
RNA interference of intracellular peptidases	Reduced protein expression and function of PEPT1 in Caco-2 cells and C. elegans	Translational, functional	Benner et al. (1973)
Sodium–proton exchanger NHE3/NHX-2	Proton export is necessary for correct function of PEPT1 in mammalian cells and in C. elegans	Functional interaction via proton gradient (protein–protein interaction not yet proven)	Kennedy et al. (2010) Watanabe et al. (2005) Pieri et al. (2006) Benner et al. (1973)
Scaffold protein PDZK1	Interacts with mouse PEPT1, trafficking to and anchoring in the plasma membrane	Direct protein–protein interaction	Sugiura et al. (1999)

AARE, amino acid responsive element; PDZ, PSD95-disc large-ZO1.