Syntaxin 1A promotes the endocytic sorting of EAAC1 leading to inhibition of glutamate transport.
The neuronal glutamate transporter, excitatory amino-acid carrier 1 (EAAC1), plays an important role in the modulation of neurotransmission and contributes to synthesis of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) and to epileptogenesis. However, the mechanisms that regulate EAAC1 endocytic sorting and function remain largely unknown. Here, we first demonstrate that EAAC1 undergoes internalization through the clathrin-mediated pathway and further show that syntaxin 1A, a key molecule in synaptic exocytosis, potentiates EAAC1 internalization, thus leading to the functional inhibition of EAAC1. In the presence of the transmembrane domain of syntaxin 1A, its H3 coiled-coil domain of syntaxin 1A is necessary and sufficient for the inhibition of EAAC1. Furthermore, specific suppression of endogenous syntaxin 1A significantly blocked EAAC1 endocytic sorting and lysosomal degradation promoted by kainic acid, a drug for kindling the animal model of human temporal lobe epilepsy in rat, indicating a potential role of syntaxin 1A in epileptogenesis. These findings provide new evidence that syntaxin 1A serves as an intrinsic enhancer to EAAC1 endocytic sorting and further suggest that syntaxin 1A is conversant with both ;ins' and ;outs' of synaptic neurotransmission.
Yu
Yong-Xin
YX
Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai, People's Republic of China.
Shen
Li
L
Xia
Peng
P
Tang
Ya-Wei
YW
Bao
Lan
L
Pei
Gang
G
D026905:Amino Acid Transport Systems / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D002478:Cells, Cultured; D002966:Clathrin / Q000378:metabolism; D003034:Coated Pits, Cell-Membrane / Q000187:drug effects / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology*; D011992:Endosomes / Q000187:drug effects; D050580:Excitatory Amino Acid Transporter 3 / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D005971:Glutamates / Q000378:metabolism*; D006801:Humans; D007608:Kainic Acid / Q000494:pharmacology; D008247:Lysosomes / Q000187:drug effects; D009474:Neurons / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D050827:Syntaxin 1 / Q000737:chemistry / Q000378:metabolism*
D026905:Amino Acid Transport Systems; D002966:Clathrin; D050580:Excitatory Amino Acid Transporter 3; D005971:Glutamates; D012333:RNA, Messenger; C493398:Slc1a1 protein, rat; C494213:Stx1a protein, rat; D050827:Syntaxin 1; D007608:Kainic Acid