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Variant-specific interaction of kinectin 1 with the multi-tRNA synthetase complex regulates ER sheet organization
Masaki Hosogane1,2, Sue-Yi Siao1, Atsushi Hatano3
1Division of Cell Proliferation, ART, Graduate School of Medicine, Tohoku University, Sendai, Miyagi 980-8575, Japan.
Iscience
|January 8, 2026
Summary
Kinectin 1 (KTN1) variants recruit the multi-tRNA synthetase complex (MSC) to the endoplasmic reticulum (ER). This interaction organizes ER sheets, revealing a new role for the MSC in cellular structure.
Area of Science:
- Cell Biology
- Molecular Biology
- Protein Interactions
Background:
- Kinectin 1 (KTN1) is an endoplasmic reticulum (ER) protein crucial for ER organization and translation.
- Alternative splicing of KTN1 generates variants, but their functional roles are largely unknown.
- The multi-tRNA synthetase complex (MSC) aggregates aminoacyl-tRNA synthetases and nonenzymatic proteins.
Purpose of the Study:
- To investigate the functional significance of KTN1 variants.
- To determine the role of KTN1 in recruiting the MSC to the ER.
- To elucidate the noncanonical functions of the MSC in ER organization.
Main Methods:
- Utilized V2 exon-specific knockout cells.
- Employed KTN1 knockout cells with variant-specific rescue.
- Investigated specific interactions between KTN1, the MSC, and glutamine-tRNA synthetase (QARS).
Main Results:
- The V2 exon of KTN1 is essential for recruiting the MSC to the ER.
- KTN1 anchors the MSC to the ER in a V2 exon-dependent manner.
- This interaction facilitates the formation of rough ER stacks.
Conclusions:
- KTN1 exhibits a variant-specific role in anchoring the MSC to the ER.
- The KTN1-MSC interaction represents a noncanonical function of the MSC.
- This interaction is critical for regulating ER sheet organization.
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