Distribution and pharmacology of alanine-serine-cysteine transporter 1 (asc-1) in rodent brain.
A polyclonal antibody against the Na+-independent alanine-serine-cysteine transporter 1 (asc-1) was raised and the specificity of the antibody verified by Western blots performed on membranes prepared from HEK293 cells transiently transfected with the cloned murine asc-1. The antibody was then used to localize the transporter in the brain of two rodent species by using immunohistochemistry at the light and electron microscopical level. asc-1-immunoreactivity (asc-1-ir) was widely distributed throughout the mouse and rat brain. Areas with high levels of asc-1-ir included hypothalamus, the medial septal area, globus pallidus, entopeduncular nucleus, cingulate and retrosplenial cortices. Moderate asc-1-ir was observed in several areas including layers III and V of the neocortex, thalamus, nucleus accumbens, caudate putamen, bed nucleus of stria terminalis, all amygdaloid nuclei, hippocampus (CA1-CA3 and hilus of the dentate gyrus), as well as several brainstem nuclei. asc-1-ir was observed as punctuate staining consistent with varicosities matching neuronal cell bodies and dendritic fields. At the ultrastructural level, asc-1-ir was mainly confined to presynaptic terminals. Immunostaining in either glial cell bodies or perivascular sites was not observed and white matter was completely devoid of asc-1-ir. Furthermore, the pharmacology of the Na+-independent uptake site for [3H]d-serine in rat brain synaptosomal P2 fractions was compared with the substrate specificity of the cloned human asc-1 transporter and a high degree of correlation was demonstrated. We conclude that asc-1-ir is widespread in the brain and limited to neuronal structures and that asc-1 may contribute to synaptic clearance of d-serine in brain.
Helboe
Lone
L
H. Lundbeck A/S, Biological Research, Department of Molecular Disease Biology, Ottiliavej 9, DK-2500 Valby, Denmark.
Egebjerg
Jan
J
Møller
Morten
M
Thomsen
Christian
C
D000409:Alanine / Q000378:metabolism / Q000494:pharmacology; D026924:Amino Acid Transport System A / Q000037:antagonists & inhibitors; D026962:Amino Acid Transport System ASC / Q000037:antagonists & inhibitors; D027062:Amino Acid Transport System L / Q000037:antagonists & inhibitors; D027182:Amino Acid Transport System y+ / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism* / Q000648:ultrastructure; D001923:Brain Chemistry; D002460:Cell Line; D003545:Cysteine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian; D027261:Fusion Regulatory Protein-1 / Q000235:genetics / Q000378:metabolism; D005998:Glycine / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007668:Kidney; D008297:Male; D051379:Mice; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012694:Serine / Q000378:metabolism / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism / Q000494:pharmacology; D013574:Synaptosomes / Q000378:metabolism / Q000648:ultrastructure; D014162:Transfection; D015091:beta-Alanine / Q000031:analogs & derivatives* / Q000494:pharmacology
D026924:Amino Acid Transport System A; D026962:Amino Acid Transport System ASC; D027062:Amino Acid Transport System L; D027182:Amino Acid Transport System y+; D027261:Fusion Regulatory Protein-1; D012333:RNA, Messenger; C498799:SLC7A10 protein, human; C412624:Slc7a10 protein, mouse; C583864:Slc7a10 protein, rat; D015091:beta-Alanine; C012924:2,2-dimethyl-beta-alanine; D012694:Serine; D012964:Sodium; D003545:Cysteine; D000409:Alanine; D005998:Glycine