Vascular Endothelium - Tissue Functioning and Remodeling in the Circulatory and Ventilatory Systems - page 515

a substrate for nitric oxide [ 951 ]. The y + transport is mediated by ubiquitous
plasmalemmal CATs (CAT1, or SLC7a1, CAT2a-CAT2b, CAT3, and CAT4).
The y + L transport system is sensitive to neutral amino acids. It has a reduced
affinity in the absence of Na + cation. It recognizes cationic amino acids in
the absence of Na + , but it requires sodium to interact with neutral amino acids.
The exchangeable y + -like transport is mediated by y + L amino acid transporters
(y + LAT), such as y + LAT1 (SLC7a7) and y + LAT2 (SLC7a6).
The B 0 , + transport system, which is sensitive to cystine, is another route that
use B 0 , + AT1 carrier. The substrate specificity of B 0 , + and b 0 , + transport systems
is similar, but the former also accepts alanine and serine. The B 0 , + transport is
mediated by SLC3a1 carrier (cystine, dibasic and neutral amino acid transporters),
or B 0 , + -type amino acid transport 76 Activator of cystine, dibasic and neutral amino
acid transport possesses variants (SLC3a1 variant-B2-SLC3a1 variant-G2).
The b 0 , + transport system recognizes cationic and neutral amino acids with a
similar affinity. It carries amino acids independently of sodium. The b 0 , + transport
system depends on both Na + and Cl − ions. It conveys cationic and neutral amino
acids with the highest affinity for hydrophobic amino acids. The b 0 , + transport is
mediated by SLC7a9 carrier (glycoprotein-associated amino acid transporter light
chain, b 0 , + transport system), a.k.a. cationic amino acid transporter of y + transport
system and B 0 , + -type amino acid transporter BAT1, B 0 , + AT, a n d b 0 , + -type amino
acid transporter (b 0 , + AT ) . 77
Transcripts (mRNAs) of amino acid transporters CAT1, LAT1, LAT2, y + LAT1,
y + LAT2, and b 0 , + AT are expressed together with the heterodimeric glycoproteins
SLC3a2 carrier (activator of dibasic and neutral amino acid transport) 78 and rBAT

transporter.
In fact, the amino acid transporter systems L, y + L, x c ,asc,andb 0 , + represented
by transporter light chains require interaction via a disulfide bridge with the type-2
membrane glycoproteins — heavy chains — for transmembrane transfer. System L,
y + L, x c , and asc require SLC3a2, whereas system b 0 , + requires rBAT subunit.
The x c transport system relies on SLC7A11 carrier, also called cystine/glutamate
transporter xCT and anionic amino acid transporter light chain. 79 The asc transport
system is based on neutral amino acid transporter SLC7a10 that corresponds to the
light chain of the dimeric carrier.
In endothelial cells, arginine uptake does not depend on extracellular Na + and
Cl − , but is inhibited by neutral amino acid glutamine and leucine. In addition,
molecules can be modified during endothelial transit.

76 A.k.a. neutral and basic amino acid transport nbAT and rBAT as well as cystinuria protein-1
(Csnu1).
77 A.k.a. cystinuria protein-3 (Csnu3).
78 A.k.a. 4F2 cell-surface antigen heavy chain (4F2HC).
79 A.k.a. calcium channel blocker resistance protein CCBR1.