Figure 5.

Circuit/subsystem diagram for IAA polar and lateral transport. This diagram is based on studies showing that IAA polar transport involves an IAA-influx protein carrier encoded by the AUX1 gene, whereas IAA efflux involves the activity of at least two membrane-bound and -associated proteins. One of these is a trans-membrane transport protein, which is encoded by members of the PIN gene family. The second are ABCB transporter proteins. See text for additional details. PP2A, protein phosphatase 2A; RCN1, Arabidopsis roots curl in NPA1 gene.