Auxin transport and a graviresponse in plants: Relevance to ABC proteins

Abstract

Phospho-glycoproteins (PGPs) belong to the ATP-binding cassette protein subfamily B (ABCB) subgroup of the ATP-binding cassette (ABC) transporter superfamily. The involvement of ABCB proteins in auxin transport is first suggested base on the results of expression levels of PGP1/ABCB1. PGPs have also been shown to mediate the cellular and long-distance transport of auxin. Interactions among PIN-formed and P-glycoprotein in auxin transport have been shown although PINs and PGPs characterize coordinated and independent auxin transport mechanisms. ABC (ABCB)/PGP is also suggested to have an important role in a graviresponse in plants. This review is describing auxin transport and a graviresponse in plants focused on structures and functions of ABC proteins.