Unidirectional arginine transport in reconstituted plasma-membrane vesicles from yeast overexpressing CAN1.
Amino acids are accumulated in Saccharomyces cerevisiae by strictly unidirectional influx systems. To see whether cellular compartmentation causes this unusual amino-acid-transport behaviour, arginine transport was studied in plasma-membrane vesicles. The arginine permease gene CAN1 was overexpressed in S. cerevisiae RH218a and in a permease-deficient mutant RS453 (can1). Reconstituted plasma-membrane vesicles from these transformants, energized by incorporated cytochrome-c oxidase, showed 3-4-fold increased rates of arginine uptake compared to vesicles from wild-type cells. The KT values were 32.5 microM in vesicles from wild-type and 28.6 microM in vesicles from transformed cells; the corresponding in vivo values were 17.5 microM and 11.4 microM, respectively. It could be demonstrated that unidirectional arginine transport and accumulation also exist in vesicles; thus, unidirectional influx is not related to cellular compartmentation.
Opekarová
M
M
Institute of Microbiology, Czechoslovak Academy of Sciences, Prague.
Caspari
T
T
Tanner
W
W
D026905:Amino Acid Transport Systems; D026923:Amino Acid Transport Systems, Basic; D001120:Arginine / Q000378:metabolism*; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism*; D015870:Gene Expression; D007700:Kinetics; D008081:Liposomes / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D014170:Transformation, Genetic
D026905:Amino Acid Transport Systems; D026923:Amino Acid Transport Systems, Basic; C502212:CAN1 protein, S cerevisiae; D008081:Liposomes; D026901:Membrane Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; C043909:arginine permease; D001120:Arginine