A molecular mechanism for LINC complex branching by structurally diverse SUN-KASH 6:6 assemblies.Gurusaran, M., Davies, O.R.
(2021) Elife 10
- PubMed: 33393904
- DOI: https://doi.org/10.7554/eLife.60175
- Primary Citation of Related Structures:
6R15, 6R16, 6R2I
- PubMed Abstract:
The Linker of Nucleoskeleton and Cytoskeleton (LINC) complex mechanically couples cytoskeletal and nuclear components across the nuclear envelope to fulfil a myriad of cellular functions, including nuclear shape and positioning, hearing, and meiotic chromosome movements. The canonical model is that 3:3 interactions between SUN and KASH proteins underlie the nucleocytoskeletal linkages provided by the LINC complex. Here, we provide crystallographic and biophysical evidence that SUN-KASH is a constitutive 6:6 complex in which two constituent 3:3 complexes interact head-to-head. A common SUN-KASH topology is achieved through structurally diverse 6:6 interaction mechanisms by distinct KASH proteins, including zinc-coordination by Nesprin-4. The SUN-KASH 6:6 interface provides a molecular mechanism for the establishment of integrative and distributive connections between 3:3 structures within a branched LINC complex network. In this model, SUN-KASH 6:6 complexes act as nodes for force distribution and integration between adjacent SUN and KASH molecules, enabling the coordinated transduction of large forces across the nuclear envelope.
Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom.