InterPro domain: IPR004776

This entry represents a mostly uncharacterised family of membrane transport proteins found in eukaryotes, bacteria and archaea. Most characterised members of this family are the PIN components of auxin efflux systems from plants. These carriers are saturable, auxin-specific, and localized to the basal ends of auxin transport-competent cells [ 1 , 2 ]. Plants typically posses several of these proteins, each displaying a unique tissue-specific expression pattern. They are expressed in almost all plant tissues including vascular tissues and roots, and influence many processes including the establishment of embryonic polarity, plant growth, apical hook formation in seedlings and the photo- and gravitrophic responses. These plant proteins are typically 600-700 amino acyl residues long and exhibit 8-12 transmembrane segments.

1. Auxin transport. Curr. Opin. Plant Biol. 8, 494-500
2. PIN and AUX/LAX proteins: their role in auxin accumulation. Trends Plant Sci. 9, 578-82