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Identification and characterization of LFD 1, a novel protein involved in membrane merger during cell fusion in N eurospora crassa
Author(s) -
PalmaGuerrero Javier,
Leeder Abigail C.,
Welch Juliet,
Glass N. Louise
Publication year - 2014
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12545
Subject(s) - biology , mutant , microbiology and biotechnology , cell fusion , lipid bilayer fusion , fusion protein , transmembrane protein , neurospora crassa , crassa , biochemistry , cell , gene , membrane , recombinant dna , receptor
Summary Despite its essential role in development, molecular mechanisms of membrane merger during cell–cell fusion in most eukaryotic organisms remain elusive. In the filamentous fungus N eurospora crassa , cell fusion occurs during asexual spore germination, where genetically identical germlings show chemotropic interactions and cell–cell fusion. Fusion of germlings and hyphae is required for the formation of the interconnected mycelial network characteristic of filamentous fungi. Previously, a multipass membrane protein, PRM1 , was characterized and acts at the step of bilayer fusion in N . crassa . Here we describe the identification and characterization of lfd‐1 , encoding a single pass transmembrane protein, which is also involved in membrane merger. lfd‐1 was identified by a targeted analysis of a transcriptional profile of a transcription factor mutant (Δ pp‐1 ) defective in germling fusion. The Δ lfd‐1 mutant shows a similar, but less severe, membrane merger defect as a Δ Prm1 mutant. By genetic analyses, we show that LFD 1 and PRM1 act independently, but share a redundant function. The cell fusion frequency of both Δ lfd‐1 and Δ Prm1 mutants was sensitive to extracellular calcium concentration and was associated with an increase in cell lysis, which was suppressed by a calcium‐dependent mechanism involving a homologue to synaptotagmin.