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Functional and Structural Insights Into Complex Formation Between OPTN Leucine Zipper Domain and RAB8A
Kei Okatsu1, Reika Kikuchi2,3, Noriyuki Matsuda3
1Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan.
Optineurin (OPTN) regulates vesicular trafficking and selective autophagy by interacting with RAB8A. This interaction, elucidated by crystal structure, is crucial for recruiting ATG9A vesicles, highlighting OPTN's multifunctional role.
Area of Science:
- Molecular biology
- Cell biology
- Structural biology
Background:
- Optineurin (OPTN) is a multifunctional adaptor protein.
- OPTN plays roles in vesicular trafficking and selective autophagy.
Purpose of the Study:
- Investigate the molecular mechanism of OPTN in regulating vesicular trafficking and selective autophagy.
- Elucidate the role of the leucine zipper (LZ) domain in OPTN function.
Main Methods:
- Determined the crystal structure of the OPTN-RAB8A complex.
- Performed structure-guided mutational analysis.
- Utilized cell biological approaches and knockout cell lines.
Main Results:
- OPTN interacts with RAB8A and related RAB proteins (RAB8B, RAB10).
- Crystal structure revealed specific interaction surfaces between OPTN and RAB8A, distinct from the LZ domain.
- RAB8A/8B/10 were not essential for mitophagy, but OPTN's RAB8A-binding residues were critical for ATG9A vesicle recruitment.
Conclusions:
- The study provides molecular insights into how OPTN regulates vesicular trafficking and selective autophagy.
- The LZ domain of OPTN is key to its multifunctional roles.
- OPTN's interaction with RAB8A is critical for specific cellular processes like ATG9A vesicle recruitment.
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