Activation of L-arginine transport by protein kinase C in rabbit, rat and mouse alveolar macrophages.
1. The role of protein kinase C in controlling L-arginine transport in alveolar macrophages was investigated. 2. L-[3H]Arginine uptake in rabbit alveolar macrophages declined by 80 % after 20 h in culture. 4beta-Phorbol 12-myristate 13-acetate (PMA), but not 4alpha-phorbol 12-myristate 13-acetate (alpha-PMA), present during 20 h culture, enhanced L-[3H]arginine uptake more than 10-fold. Staurosporine and chelerythrine opposed this effect. 3. L-[3H]Arginine uptake was saturable and blockable by L-lysine. After PMA treatment Vmax was increased more than 5-fold and Km was reduced from 0.65 to 0.32 mM. 4. Time course experiments showed that PMA increased L-[3H]arginine uptake almost maximally within 2 h. This short-term effect was not affected by cycloheximide or actinomycin D. 5. L-[3H]Arginine uptake and its stimulation by PMA was also observed in sodium-free medium. 6. L-Leucine (0.1 mM) inhibited L-[3H]arginine uptake by 50 % in sodium-containing medium, but not in sodium-free medium. At 1 mM, L-leucine caused significant inhibition in sodium-free medium also. L-Leucine showed similar effects on PMA-treated cells. 7. N-Ethylmaleimide (200 microM, 10 min) reduced L-[3H]arginine uptake by 70 % in control cells, but had no effect on PMA-treated (20 or 2 h) cells. 8. In alveolar macrophages, multiple transport systems are involved in L-arginine uptake, which is markedly stimulated by protein kinase C, probably by modulation of the activity of already expressed cationic amino acid transporters.
Racké
K
K
Institute of Pharmacology and Toxicology, University of Bonn, Reuterstrasse 2b, D-53113 Bonn, Germany. racke.kurt@uni-bonn.de
Hey
C
C
Mössner
J
J
Hammermann
R
R
Stichnote
C
C
Wessler
I
I
D026923:Amino Acid Transport Systems, Basic; D000818:Animals; D001120:Arginine / Q000493:pharmacokinetics*; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D002273:Carcinogens / Q000494:pharmacology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D005260:Female; D007700:Kinetics; D007930:Leucine / Q000494:pharmacology; D016676:Macrophages, Alveolar / Q000737:chemistry / Q000201:enzymology*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008815:Mice, Inbred Strains; D011493:Protein Kinase C / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000494:pharmacology; D013045:Species Specificity; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014316:Tritium
D026923:Amino Acid Transport Systems, Basic; D002273:Carcinogens; D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; D012333:RNA, Messenger; D014316:Tritium; D001120:Arginine; D012964:Sodium; D011493:Protein Kinase C; D007930:Leucine; D013755:Tetradecanoylphorbol Acetate; D005033:Ethylmaleimide