<p>For Fig 1C: All blots_for Fig1C.</p>

Z-discs play a key role in cardiac signalling and disease, however, the arrangement and function of many of the proteins present in the Z-disc remain to be understood. Here, we determined the organisation of 3 key proteins, ZASP, ɑ-actinin-2 and the Z1Z2 epitope of titin, located within the Z-disc.

We fluorescently labelled these proteins in cardiac myofibrils using Adhirons specific to each protein and used interferometric photoactivated localization microscopy (iPALM) to obtain the 3D position of these proteins to a high precision (<10nm in x,y,z). We then used PERPL (Pattern Extraction from Relative Positions of Localisations: available at <a href="github.com/oubino/z_disk/releases/tag/v0.0.3" target="_blank">github.com/oubino/z_disk/releases/tag/v0.0.3</a>) to analyse patterns in the relative positions of the proteins and reveal their underlying organisation.