Model of early auxin signaling to cell division and cell elongation in the tobacco cell line VBI-0. A receptor with high affinity for NAA (presumably ABP1) triggers cell elongation, a second un- identified receptor with high affinity for 2,4-D (Rx) activates cell division through a trimeric G-protein. Both pathways are connected by a negative crosstalk (dashed lines 1 and 2). DP stays for a generic docking protein activated by G-proteins.