Triads in skeletal muscle constitute the basis of excitation-contraction coupling as the cradle of the calcium release complex. We showed previously that triadin, a member of this complex, has shaping properties on reticulum membrane and is indirectly involved in a link between triads and microtubules. We have identified here CLIMP-63 as the partner of triadin responsible of this association triads/microtubules. Triadin and CLIMP-63 interact via their respective luminal domains and the shaping properties of triadin depend on the capacity of CLIMP-63 to bind microtubules with its cytosolic part. In skeletal muscle, CLIMP-63 is localized in the sarcoplasmic reticulum, including triads, and is associated to the calcium release complex via its interaction with triadin. Depletion of triadin in triadin KO muscles results in the delocalization of CLIMP-63 from triads, its dissociation from the calcium release complex and a disorganization of the microtubule network. Our results suggest that the association of triadin and CLIMP-63 could be involved in the shaping of SR terminal cisternae and in the guidance of microtubules close to the triads.
- Received March 3, 2016.
- Accepted August 18, 2016.
- © 2016. Published by The Company of Biologists Ltd