A functional Rim101 complex is required for proper accumulation of the Ena1 Na+-ATPase protein in response to salt stress in Saccharomyces cerevisiae.
The maintenance of ionic homeostasis is essential for cell viability, thus the activity of plasma membrane ion transporters must be tightly controlled. Previous studies in Saccharomyces cerevisiae revealed that the proper trafficking of several nutrient permeases requires the E3 ubiquitin ligase Rsp5 and, in many cases, the presence of specific adaptor proteins needed for Rsp5 substrate recognition. Among these adaptor proteins are nine members of the arrestin-related trafficking adaptor (ART) family. We studied the possible role of the ART family in the regulation of monovalent cation transporters. We show here that the salt sensitivity phenotype of the rim8/art9 mutant is due to severe defects in Ena1 protein accumulation, which is not attributable to transcriptional defects. Many components of the Rim pathway are required for correct Ena1 accumulation, but not for the accumulation of other nutrient permeases. Moreover, we observe that strains lacking components of the endosomal sorting complexes required for transport (ESCRT) pathway previously described to play a role in Rim complex formation present similar defects in Ena1 accumulation. Our results show that, in response to salt stress, a functional Rim complex via specific ESCRT interactions is required for the proper accumulation of the Ena1 protein, but not induction of the ENA1 gene.
Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avd. de los Naranjos s/n, Valencia 46022, Spain.
M Carmen
MC
Marqués
Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avd. de los Naranjos s/n, Valencia 46022, Spain.
Sara
S
Zamarbide-Forés
Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avd. de los Naranjos s/n, Valencia 46022, Spain.
Leda
L
Pedelini
Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avd. de los Naranjos s/n, Valencia 46022, Spain.
Vicent
V
Llopis-Torregrosa
Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avd. de los Naranjos s/n, Valencia 46022, Spain lynne@ibmcp.upv.es.
Lynne
L
Yenush
D015966:Gene Expression Regulation, Fungal; D009997:Osmotic Pressure; D012097:Repressor Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000201:enzymology* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D012492:Salts / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
C086375:ENA1 protein, S cerevisiae; C489601:RIM101 protein, S cerevisiae; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D012492:Salts; D000254:Sodium-Potassium-Exchanging ATPase
ENA1; ESCRT pathway; Rim101 pathway; ion transport; protein trafficking; salt stress