High impact information on AAP1

• We independently identified the location of the N and C termini using immunofluorescence microscopy of NAT2 expressed in COS-1 cells [1].
• AAP1 was electrogenic; there was an amino acid-induced depolarization of the oocyte plasma membrane and net inward currents through the transporter due to the transport of amino acids favoring neutral amino acids with shortside chains [2].
• The density of particles on the protoplasmic face of the plasma membrane of oocytes expressing AAP1 increased approximately 5-fold above water-injected controls and corresponded to a turnover number 350 to 800 s-1 [2].
• The amino acid transporter AAP1/NAT2 recently cloned from Arabidopsis thaliana was expressed in Xenopus oocytes, and we used electrophysiological, radiotracer flux, and electron microscopic methods to characterize the biophysical properties, kinetics, and specificity of the transporter [2].
• The two genes AAP1 and AAP2 encode broad specificity H(+)-amino acid co-transporters and are expressed to high levels in siliques of Arabidopsis, indicating a potential role in supplying the seeds with organic nitrogen [3].

Associations of AAP1 with chemical compounds

• Thus, AAP2 is less selective as compared with AAP1 and transports basic amino acids such as histidine as shown by expression in a histidine transport-deficient yeast strain [4].
• The growth and uptake studies identified glutamate, histidine and neutral amino acids, including phenylalanine, as physiological substrates for AAP1, whereas aspartate, lysine and arginine are not [5].

References