DIX Domain Polymerization Drives Assembly of Plant Cell Polarity Complexes.
Cell 2020;
180:427-439.e12. [PMID:
32004461 PMCID:
PMC7042713 DOI:
10.1016/j.cell.2020.01.011]
[Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 10/18/2019] [Accepted: 01/06/2020] [Indexed: 11/28/2022]
Abstract
Cell polarity is fundamental for tissue morphogenesis in multicellular organisms. Plants and animals evolved multicellularity independently, and it is unknown whether their polarity systems are derived from a single-celled ancestor. Planar polarity in animals is conferred by Wnt signaling, an ancient signaling pathway transduced by Dishevelled, which assembles signalosomes by dynamic head-to-tail DIX domain polymerization. In contrast, polarity-determining pathways in plants are elusive. We recently discovered Arabidopsis SOSEKI proteins, which exhibit polar localization throughout development. Here, we identify SOSEKI as ancient polar proteins across land plants. Concentration-dependent polymerization via a bona fide DIX domain allows these to recruit ANGUSTIFOLIA to polar sites, similar to the polymerization-dependent recruitment of signaling effectors by Dishevelled. Cross-kingdom domain swaps reveal functional equivalence of animal and plant DIX domains. We trace DIX domains to unicellular eukaryotes and thus show that DIX-dependent polymerization is an ancient mechanism conserved between kingdoms and central to polarity proteins.
SOSEKI proteins are deeply conserved polar proteins in land plants
A DIX domain mediates polymerization and polarization of SOSEKI proteins
SOSEKI polymerization allows polar recruitment of an effector protein
DIX-dependent polymerization is shared between animal and plant polarity proteins
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