title: Post-translational modification directs nuclear and hyphal tip localization of Candida albicans mRNA-binding protein Slr1.
abstract: The morphological transition of the opportunistic fungal pathogen Candida albicans from budding to hyphal growth has been implicated in its ability to cause disease in animal models. Absence of SR-like RNA-binding protein Slr1 slows hyphal formation and decreases virulence in a systemic candidiasis model, suggesting a role for post-transcriptional regulation in these processes. SR (serine-arginine)-rich proteins influence multiple steps in mRNA metabolism and their localization and function are frequently controlled by modification. We now demonstrate that Slr1 binds to polyadenylated RNA and that its intracellular localization is modulated by phosphorylation and methylation. Wildtype Slr1-GFP is predominantly nuclear, but also co-fractionates with translating ribosomes. The non-phosphorylatable slr1-6SA-GFP protein, in which six serines in SR/RS clusters are substituted with alanines, primarily localizes to the cytoplasm in budding cells. Intriguingly, hyphal cells display a slr1-6SA-GFP focus at the tip near the Spitzenkörper, a vesicular structure involved in molecular trafficking to the tip. The presence of slr1-6SA-GFP hyphal tip foci is reduced in the absence of the mRNA-transport protein She3, suggesting that unphosphorylated Slr1 associates with mRNA-protein complexes transported to the tip. The impact of SLR1 deletion on hyphal formation and function thus may be partially due to a role in hyphal mRNA transport.
authors.affiliation: Biology Department, Bowdoin College, Brunswick, ME, 04011, USA.
authors.forename: Chaiyaboot
authors.initials: C
authors.lastname: Ariyachet
authors.affiliation: Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften, Georg-August Universität Göttingen, Göttingen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Beißel
authors.affiliation: Biology Department, Bowdoin College, Brunswick, ME, 04011, USA.
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.affiliation: Biology Department, Bowdoin College, Brunswick, ME, 04011, USA.
authors.forename: Selena
authors.initials: S
authors.lastname: Lorrey
authors.affiliation: Biology Department, Bowdoin College, Brunswick, ME, 04011, USA.
authors.forename: Olivia
authors.initials: O
authors.lastname: Mackenzie
authors.affiliation: Biology Department, Bowdoin College, Brunswick, ME, 04011, USA.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Martin
authors.affiliation: Biology Department, Bowdoin College, Brunswick, ME, 04011, USA.
authors.forename: Katharine
authors.initials: K
authors.lastname: O'Brien
authors.affiliation: Biology Department, Bowdoin College, Brunswick, ME, 04011, USA.
authors.forename: Tossapol
authors.initials: T
authors.lastname: Pholcharee
authors.affiliation: Biology Department, Bowdoin College, Brunswick, ME, 04011, USA.
authors.forename: Sue
authors.initials: S
authors.lastname: Sim
authors.affiliation: Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften, Georg-August Universität Göttingen, Göttingen, Germany.
authors.forename: Heike
authors.initials: H
authors.lastname: Krebber
authors.affiliation: Biology Department, Bowdoin College, Brunswick, ME, 04011, USA.
authors.forename: Anne E
authors.identifier: http://orcid.org/0000-0003-3381-672X
authors.initials: AE
authors.lastname: McBride
mesh_terms: D002176:Candida albicans / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D017353:Gene Deletion; D025301:Hyphae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins