Transport and distribution of florigen FT. (Left) The FT gene is transcribed and translated within the phloem companion cell. Following this, the FT protein interacts with the FTIP1 protein located on the ER. Subsequently, the FT protein is transported to the sieve element through plasmodesmata. In the sieve element, FT interacts with the NaKR1 protein that facilitates transport through the phloem. (Right) Upon arrival to the shoot apex, FT is unloaded from the vascular tissue and directed toward the SAM, facilitated by a combination of selective movement and diffusion. The transport of FT is believed to be modulated by callose, a compound that regulates the permeability of plasmodesmata. Within the SAM, FT proteins do not extend to its periphery.