RRC ID 27185
Author Eckler AM, Wilder C, Castanon A, Ferris VM, Lamere RA, Perrin BA, Pearlman R, White B, Byrd C, Ludvik N, Nichols N, Poole-Sumrall K, Sztul E, Styers ML.
Title Haploinsufficiency of the Sec7 guanine nucleotide exchange factor gea1 impairs septation in fission yeast.
Journal PLoS ONE
Abstract Membrane trafficking is essential to eukaryotic life and is controlled by a complex network of proteins that regulate movement of proteins and lipids between organelles. The GBF1/GEA family of Guanine nucleotide Exchange Factors (GEFs) regulates trafficking between the endoplasmic reticulum and Golgi by catalyzing the exchange of GDP for GTP on ADP Ribosylation Factors (Arfs). Activated Arfs recruit coat protein complex 1 (COP-I) to form vesicles that ferry cargo between these organelles. To further explore the function of the GBF1/GEA family, we have characterized a fission yeast mutant lacking one copy of the essential gene gea1 (gea1+/-), the Schizosaccharomyces pombe ortholog of GBF1. The haploinsufficient gea1+/- strain was shown to be sensitive to the GBF1 inhibitor brefeldin A (BFA) and was rescued from BFA sensitivity by gea1p overexpression. No overt defects in localization of arf1p or arf6p were observed in gea1+/- cells, but the fission yeast homolog of the COP-I cargo sac1 was mislocalized, consistent with impaired COP-I trafficking. Although Golgi morphology appeared normal, a slight increase in vacuolar size was observed in the gea1+/- mutant strain. Importantly, gea1+/- cells exhibited dramatic cytokinesis-related defects, including disorganized contractile rings, an increased septation index, and alterations in septum morphology. Septation defects appear to result from altered secretion of enzymes required for septum dynamics, as decreased secretion of eng1p, a β-glucanase required for septum breakdown, was observed in gea1+/- cells, and overexpression of eng1p suppressed the increased septation phenotype. These observations implicate gea1 in regulation of septum breakdown and establish S. pombe as a model system to explore GBF1/GEA function in cytokinesis.
Volume 8(2)
Pages e56807
Published 2013
DOI 10.1371/journal.pone.0056807
PII PONE-D-12-28567
PMID 23457617
PMC PMC3574105
MeSH ADP-Ribosylation Factors / metabolism Biological Transport / drug effects Biological Transport / genetics Brefeldin A / pharmacology Cell Division / drug effects Cell Division / genetics* Cytokinesis / drug effects Cytokinesis / genetics Guanine Nucleotide Exchange Factors / antagonists & inhibitors Guanine Nucleotide Exchange Factors / deficiency Guanine Nucleotide Exchange Factors / genetics* Haploinsufficiency* Organelles / drug effects Organelles / genetics Schizosaccharomyces / cytology* Schizosaccharomyces / drug effects Schizosaccharomyces / enzymology Schizosaccharomyces / genetics*
IF 2.766
Times Cited 0
DNA material pDUAL-YFH1c (RDB06151) SpYFH30G11 (SPW092155) SpYFH39H12 (SPW095780) SpYFH13E01 (SPW085297) SpYFH36D10 (SPW094482) SpYFH36G05 (SPW094549).