Rab Effector EHBP1L1 Associates with the Tetratricopeptide Repeat Domain of Kinesin Light Chain 1

국문 초록 (Abstract)

Kinesin 1은 미세소관을 따라 plus말단으로 이동하는 모터단백질로 세포내 물질 수송에 관여한다. Kinesin 1은 경쇄단위체(light chain subunit)를 통하여 운반체들인, 세포내 소기관, 다양한 소포체, 신경전달물질 수용체 단백질, 세포신호전달 단백질과 여러 단백질 복합체들과 결합하여 운반하는 kinesin superfamily protein (KIFs)의 한 종류이다. Kinesin light chains 1 (KLC1)은 모터 기능이 없는 단위체로서 kinesin heavy chain (KHC)과 결합한다. KLC1은 다양한 매개단백질들과 결합하지만 아직 결합하는 매개단백질이 충분히 밝혀지지 않았다. 본 연구에서는 KLC1의 tetratricopeptide repeat (TPR) 영역과 결합하는 단백질을 분리하기 위하여 효모 two-hybrid 탐색한 결과 EH domain-binding protein 1-like 1 (EHBP1L1) 을 분리하였다. EHBP1L1은 KLC1의 TPR 영역을 포함한 부위와 결합하지만 KIF5B (kinesin 1의 모터 단백질)과 KIF3A (kinesin 2의 모터 단백질)와는 결합하지 않았다. 또한 KLC1은 EHBP1L1의 C-말단에 존재하는 coiled-coil 도메인과 결합하였으며, 다른 EHBP1L1의 isoform인 EHBP1과는 결합하지 않았다. KLC1은 GST와는 결합하지 않지만 GST-EHBP1L1과 GST-EHBP1L1-coiled-coil domain과는 결합하였다. HEK-293T세포에 EHBP1L1과 KLC1을 동시에 발현시켰을 때 두 단백질은 세포 내에서 같은 부위에 존재하며, EHBP1L1을 면역침강한 결과 KLC1뿐만 아니라 KIF5B와도 같이 침강함을 확인하였다. 이러한 결과들은 kinesin 1은 EHBP1L1이 결합한 운반체를 수송함을 시사한다.

다국어 초록 (Multilingual Abstract)

Kinesin-1 is microtubule-dependent plus-end direct molecular motor protein essential for intracellular transport. It is a member of the kinesin superfamily proteins (KIFs) which transport cargo, including organelles, vesicles, neurotransmitter receptors, cell-signaling molecules, and protein complexes through interaction between its light chain subunit and the cargo. Kinesin light chain 1 (KLC1) is a non-motor subunit that associates with the kinesin heavy chain (KHC). Although KLC1 interacts with many different adaptor proteins and scaffolding proteins, its binding proteins have not yet been fully identified. We used the yeast two-hybrid assay to identify proteins that interact with the tetratricopeptide repeat (TPR) domain of KLC1, and found an interaction between KLC1 and EH domain-binding protein 1 like 1 (EHBP1L1). EHBP1L1 bound to the region containing all six TPR repeats of KLC1 and did not interact with KIF5B (a motor protein of kinesin 1) or KIF3A (a motor protein of kinesin 2) in the yeast two-hybrid assay. The carboxyl-terminus of the coiled-coil domain of EHBP1L1 is essential for interaction with KLC1. However, another EHBP1L1 isoform, EHBP1, did not interact with KLC1 in the yeast two-hybrid assay. KLC1 interacted with GST-EHBP1L1 and its coiled-coil domain but not with GST only. When co-expressed in HEK-293T cells, EHBP1L1 co-localized with KLC1 and co-immunoprecipitated with KLC1 and KIF5B but not KIF3A. These results suggest that kinesin 1 motor protein may transport EHBP1L1-associated cargo in cells.

목차 (Table of Contents)

• Introduction
• Materials and Methods
• Results
• Discussion
• References
• 초록

참고문헌 (Reference)

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