The yeast Arf GTPase-activating protein Age1 is regulated by phospholipase D for post-Golgi vesicular transport.
Vesicular transport shuttles cargo among intracellular compartments. Several stages of vesicular transport are mediated by the small GTPase Arf, which is controlled in a cycle of GTP binding and hydrolysis by Arf guanine-nucleotide exchange factors and Arf GTPase-activating proteins (ArfGAPs), respectively. In budding yeast the Age2 + Gcs1 ArfGAP pair facilitates post-Golgi transport. We have found the AGE1 gene, encoding another ArfGAP, can in high gene-copy number alleviate the temperature sensitivity of cells carrying mutations affecting the Age2 + Gcs1 ArfGAP pair. Moreover, increased AGE1 gene dosage compensates for the complete absence of the otherwise essential Age2 + Gcs1 ArfGAP pair. Increased dosage of SFH2, encoding a phosphatidylinositol transfer protein, also allows cell growth in the absence of the Age2 + Gcs1 pair, but good growth in this situation requires Age1. The ability of Age1 to overcome the need for Age2 + Gcs1 depends on phospholipase D activity that regulates lipid composition. We show by direct assessment of Age1 ArfGAP activity that Age1 is regulated by lipid composition and can provide ArfGAP function for post-Golgi transport.
Department of Microbiology and Immunology, DalhousieUniversity, Halifax, Nova Scotia B3H 1X5, Canada.
Jeremy J R
JJ
Benjamin
Pak P
PP
Poon
Stephen M
SM
Lewis
Andréanne
A
Auger
Tania A
TA
Wong
Richard A
RA
Singer
Gerald C
GC
Johnston
D020727:ADP-Ribosylation Factors / Q000235:genetics / Q000378:metabolism; D001692:Biological Transport / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism*; D018628:Gene Dosage; D006056:Golgi Apparatus / Q000235:genetics / Q000378:metabolism*; D008563:Membrane Lipids / Q000235:genetics / Q000378:metabolism*; D010739:Phospholipase D / Q000235:genetics / Q000378:metabolism*; D049294:Phospholipid Transfer Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D022161:Transport Vesicles / Q000235:genetics / Q000378:metabolism*
C444920:AGE2 protein, S cerevisiae; C557301:Age1 protein, S cerevisiae; C483430:CSR1 protein, S cerevisiae; D004268:DNA-Binding Proteins; C089147:GCS1 protein, S cerevisiae; D020690:GTPase-Activating Proteins; D008563:Membrane Lipids; D049294:Phospholipid Transfer Proteins; D029701:Saccharomyces cerevisiae Proteins; D010739:Phospholipase D; D020727:ADP-Ribosylation Factors