RRC ID 49590
Author Curto MÁ, Moro S, Yanguas F, Gutiérrez-González C, Valdivieso MH.
Title The ancient claudin Dni2 facilitates yeast cell fusion by compartmentalizing Dni1 into a membrane subdomain.
Journal Cell Mol Life Sci
Abstract Dni1 and Dni2 facilitate cell fusion during mating. Here, we show that these proteins are interdependent for their localization in a plasma membrane subdomain, which we have termed the mating fusion domain. Dni1 compartmentation in the domain is required for cell fusion. The contribution of actin, sterol-dependent membrane organization, and Dni2 to this compartmentation was analysed, and the results showed that Dni2 plays the most relevant role in the process. In turn, the Dni2 exit from the endoplasmic reticulum depends on Dni1. These proteins share the presence of a cysteine motif in their first extracellular loop related to the claudin GLWxxC(8-10 aa)C signature motif. Structure-function analyses show that mutating each Dni1 conserved cysteine has mild effects, and that only simultaneous elimination of several cysteines leads to a mating defect. On the contrary, eliminating each single cysteine and the C-terminal tail in Dni2 abrogates Dni1 compartmentation and cell fusion. Sequence alignments show that claudin trans-membrane helixes bear small-XXX-small motifs at conserved positions. The fourth Dni2 trans-membrane helix tends to form homo-oligomers in Escherichia plasma membrane, and two concatenated small-XXX-small motifs are required for efficient oligomerization and for Dni2 export from the yeast endoplasmic reticulum. Together, our results strongly suggest that Dni2 is an ancient claudin that blocks Dni1 diffusion from the intercellular region where two plasma membranes are in close proximity, and that this function is required for Dni1 to facilitate cell fusion.
Volume 75(9)
Pages 1687-1706
Published 2018-5-1
DOI 10.1007/s00018-017-2709-4
PII 10.1007/s00018-017-2709-4
PMID 29134248
MeSH Amino Acid Sequence Cell Fusion Cell Membrane / metabolism* Conserved Sequence Membrane Fusion* / genetics Membrane Microdomains / metabolism Membrane Proteins / metabolism* Organisms, Genetically Modified Protein Transport / genetics Schizosaccharomyces / genetics Schizosaccharomyces / physiology* Schizosaccharomyces pombe Proteins / genetics Schizosaccharomyces pombe Proteins / metabolism Schizosaccharomyces pombe Proteins / physiology* Sequence Alignment
IF 6.496
Times Cited 2
Yeast FYP1557 FYP1558