title: Characterization of MYR1, a dosage suppressor of YPT6 and RIC1 deficient mutants.
abstract: Membrane traffic is tightly regulated and the Rab protein family of small GTPases plays a central role in this regulation. One member of this family is the Saccharomyces cerevisae protein Ypt6. To search for new genes interacting with Ypt6-related pathways, we performed a genetic screen for high copy suppressors of ypt6Delta temperature sensitivity at 35 degrees C. Among the suppressors, MYR1 was also able to suppress the temperature sensitive mutant lacking Ric1, a subunit of the Ypt6 guanine exchanging factor complex Ric1/Rgp1. Myr1 is characterized by a coiled coil region and a GYF domain, a protein module binding proline-rich sequences. Myr1 is able to bind membranes but is also associated with larger structures insoluble in Triton X-100. By immunofluorescence, Myr1 shows a network-like pattern as well as small foci. Overexpression of Myr1 influences nuclear envelope morphology and high levels are lethal. This lethality is rescued when the N-terminal region, containing the GYF domain, is deleted. The transcription profile of a myr1Delta strain shows effects on genes involved in nuclear migration, Ras signalling and transcription. Taken together, these results suggest that Myr1 is a novel factor linked to the secretory pathway and important cellular regulatory mechanisms.
authors.affiliation: School of Life Sciences, Södertörns Högskola, 141 89, Huddinge, Sweden.
authors.forename: Alexander
authors.initials: A
authors.lastname: Georgiev
authors.forename: Arunas
authors.initials: A
authors.lastname: Leipus
authors.forename: Ida
authors.initials: I
authors.lastname: Olsson
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Berrez
authors.forename: Ann
authors.initials: A
authors.lastname: Mutvei
mesh_terms: D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D053144:Cell Nucleus Shape; D017124:Conserved Sequence; D020662:Guanine Nucleotide Exchange Factors; D008565:Membrane Proteins; D020559:Monomeric GTP-Binding Proteins / Q000172:deficiency / Q000235:genetics*; D017830:Octoxynol; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D017384:Sequence Deletion; D015398:Signal Transduction; D012995:Solubility; D013489:Suppression, Genetic / Q000235:genetics*; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics*; D018631:ras Proteins / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins
chemical_list: D002352:Carrier Proteins; D020662:Guanine Nucleotide Exchange Factors; D008565:Membrane Proteins; D020559:Monomeric GTP-Binding Proteins; D017830:Octoxynol; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D018631:ras Proteins; C529873:Myr1 protein, S cerevisiae; D047908:Intracellular Signaling Peptides and Proteins; C105592:RIC1 protein, S cerevisiae; C499307:YPT6 protein, S cerevisiae