The unexpected versatility of ALP/Enigma family proteins

Figures

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  FIGURE 1. Origin and distribution of ALP/Enigma proteins in the metazoan tree. ALP/Enigma proteins first evolved in metazoans as evidenced by single Enigma-like proteins found for example in the ancient phyla of Porifera (the sponge Amphimedon) and Cnidaria (the sea anemone Nematostella). In Bilateria, duplication and recombination gave rise to ALP-like proteins with a single, but different LIM domain, but also to combined ALP/Enigma proteins with four LIM domains (e.g. in Drosophila and C. elegans), as well as proteins without LIM domains (Zasp66 and Zasp67 in Drosophila). The ZM domain first evolved in the ancestor of Bilateria. Evolutionary tree with representative species and the ALP/Enigma proteins with their respective proteins domains (PDZ, ZM, LIM) are shown. Arrows indicate the stem lineage where a particular group of ALP/Enigma proteins originated.

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  FIGURE 2. The sarcomere and Zasp52 during Z-disc growth (A) Structure of the sarcomere. The myosin thick filaments are linked at the M-line, and the actin thin filaments are anchored at the Z-disc. (B) Process uncovered by González-Morales et al. (2019b). During early Z-disc growth, the “growing” isoform (Zasp52) predominates and allows interaction with other Zasp proteins through the ZM/LIM interaction. During late Z-disc growth, the “blocking” isoforms with no LIM domains predominate (Zasp66 and Zasp67), which inhibits further growth of the Z-disc.