Betaine-γ-aminobutyric Acid Transporter 1 (BGT-1/mGAT2) Interacts with the PDZ Domain of Munc-18 Interacting Proteins (Mints)

Betaine-γ-aminobutyric acid transporter 1 (BGT-1/mGAT2)과 Munc-18-interacting (Mint) 단백질의 PDZ 결합

  • Kim, Sang-Jin (Department of Neurology, College of Medicine, Inje University) ;
  • Jeong, Young-Joo (Department of Biochemistry, College of Medicine, Inje University) ;
  • Choi, Sun-Hee (Department of Biochemistry, College of Medicine, Inje University) ;
  • Choi, Chun-Yeon (Department of Biochemistry, College of Medicine, Inje University) ;
  • Jun, Hee-Jae (Departments of Thoracic and Cardiovascular Surgery, College of Medicine, Inje University) ;
  • Moon, Il-Soo (Departments of Anatomy, College of Medicine, Dongguk University) ;
  • Seog, Dae-Hyun (Department of Biochemistry, College of Medicine, Inje University) ;
  • Jang, Won-Hee (Department of Biochemistry, College of Medicine, Inje University)
  • 김상진 (인제대학교 의과대학 신경과학교실) ;
  • 정영주 (인제대학교 의과대학 생화학교실) ;
  • 최선희 (인제대학교 의과대학 생화학교실) ;
  • 최춘연 (인제대학교 의과대학 생화학교실) ;
  • 전희재 (인제대학교 의과대학 흉부외과학교실) ;
  • 문일수 (동국대학교 의과대학 해부학교실) ;
  • 석대현 (인제대학교 의과대학 생화학교실) ;
  • 장원희 (인제대학교 의과대학 생화학교실)
  • Received : 2012.08.23
  • Accepted : 2012.09.07
  • Published : 2012.09.30


The action of neuronally released ${\gamma}$-aminobutyric acid (GABA) is terminated by uptake into the neurons by GABA transporters (GATs). The mechanism underlying the stabilization and regulation of GAT2 has not yet been elucidated. We used the yeast two-hybrid system to identify proteins that interact with and, thereby, regulate betaine-${\gamma}$-aminobutyric acid transporter 1 (BGT-1/mGAT2). We found an interaction between BGT-1/mGAT2 and Munc-18-interacting proteins (Mints). The "T-H-L" motif at the C-terminal end of BGT-1/mGAT2 was essential for the interaction with Mint2 in the yeast two-hybrid assay. Mint2 bound to the tail region of BGT-1/mGAT2, but not to other GAT members. When co-expressed in HEK-293T cells, Mint2 was co-immunoprecipitated with BGT-1/mGAT2. In addition, we demonstrated the cellular co-localization of BGT-1/mGAT2 and Mint2 in the cells. These results suggest that Mint2 contributes to the regulation of BGT-1/mGAT2.

${\gamma}$-Aminobutyric acid (GABA)는 신경세포 밖으로 분비된 후 GABA 수송체들(GATs)에 의하여 다시 신경세포 안으로 재흡수 된다. 그러나, GABA 수송체들이 어떻게 연접전막의 위치에 안정적으로 존재하는지 또한 어떤 단백질과 결합하여 조절을 받는지는 알려져 있지 않다. 본 연구에서 효모 two-hybrid system을 이용하여 betaine-${\gamma}$-aminobutyric acid transporter 1 (BGT-1/mGAT2)의 C-말단과 특이적으로 결합하는 Munc-18-interacting (Mint) 단백질을 분리하였다. BGT-1/mGAT2의 C-말단에 존재하는 "T-H-L" 아미노산배열은 Mint2와의 결합에 필수적으로 관여하였다. Mint2은 BGT-1/mGAT2와는 결합하지만, 다른 종류의 GAT와는 결합하지 않았다. 또한 HEK-293T 세포에 Mint2와 BGT-1/mGAT2을 동시에 발현시켜 면역침강한 결과 두 단백질은 같이 면역침강하였으며, 두 단백질은 세포 내에서 세포막 부위에 같이 존재함도 확인하였다. 이러한 결과들은 Mint2가 BGT-1/mGAT2와 결합하여 BGT-1/mGAT2을 조절하는 역할을 함을 시사한다.


Supported by : Inje University


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