Figure 4. Competitive inhibition of the transport by Lat2/CD98 using various substrates.

Amino acid-functional groups (A), proximate hydrophobic extension (B), and substituents in the 3 and 5 positions of the tyrosine ring (C) are studied. Transported substrates are highlighted in gray. Uptake of 3,3′-T₂ (100nM) in X. laevis oocytes coinjected with cRNA of CD98 and Lat2. Experiments have been performed in the absence (control) and presence of indicated substrates (A, 10μM; B and C, 1mM). Mean ± SEM of 10–15 oocytes per group of 2–3 independent experiments normalized to the uptake of 3,3′-T₂ (after subtraction of noninjected oocytes) are shown.