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CAMSAP2 and CAMSAP3 localize at microtubule intersections to regulate the spatial distribution of microtubules
Rui Zhang1,† , Lusheng Gu2,3,4,† , Wei Chen5,† , Nobutoshi Tanaka6 , Zhengrong Zhou1 , Honglin Xu1 , Tao Xu2,3,4 , Wei Ji2,3,4,* , Xin Liang5,* , Wenxiang Meng1,2,7,*
1State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
2College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
3National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
4Innovation Center of Optical Imaging and Detection Technology R&D, Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou 510320, China
5IDG/McGovern Institute for Brain Research, Tsinghua–Peking Joint Center for Life Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
6Laboratory for Cell Adhesion and Tissue Patterning, RIKEN Center for Developmental Biology/RIKEN Center for Biosystems Dynamics Research, 650-0047 Kobe, Japan
7Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
These authors contributed equally to this work
*Correspondence to:Wei Ji , Xin Liang , Wenxiang Meng ,
J Mol Cell Biol, Volume 15, Issue 8, August 2023, mjad050,
Keyword: CAMSAPs, microtubule intersections, microtubule networks

Microtubule networks support many cellular processes and exhibit a highly ordered architecture. However, due to the limited axial resolution of conventional light microscopy, the structural features of these networks cannot be resolved in three-dimensional (3D) space. Here, we used customized ultra-high-resolution interferometric single-molecule localization microscopy to characterize the microtubule networks in Caco2 cells. We found that the calmodulin-regulated spectrin-associated proteins (CAMSAPs) localize at a portion of microtubule intersections. Further investigation showed that depletion of CAMSAP2 and CAMSAP3 leads to the narrowing of the inter-microtubule distance. Mechanistically, CAMSAPs recognize microtubule defects, which often occur near microtubule intersections, and then recruit katanin to remove the damaged microtubules. Therefore, the CAMSAP–katanin complex is a regulatory module for the distance between microtubules. Taken together, our results characterize the architecture of cellular microtubule networks in high resolution and provide molecular insights into how the 3D structure of microtubule networks is controlled.