Does auxin binding protein 1 control both cell division and cell expansion?

The Auxin-Binding Protein 1 (ABP1) was identified over 30 years ago thanks to it's high affinity for active auxins. ABP1 plays an essential role in plant life yet to this day, its function remains 'enigmatic.' A recent study by our laboratory shows that ABP1 is critical for regulation of the cell cycle, acting both in G(1) and at the G(2)/M transition. We showed that ABP1 is likely to mediate the permissive auxin signal for entry into the cell cycle. These data were obtained by studying a conditional functional knock-out of ABP1 generated by cellular immunization in the model tobacco cell line, Bright Yellow 2.