title: Palmitoylation of the Cysteine Residue in the DHHC Motif of a Palmitoyl Transferase Mediates Ca2+ Homeostasis in Aspergillus.
abstract: Finely tuned changes in cytosolic free calcium ([Ca2+]c) mediate numerous intracellular functions resulting in the activation or inactivation of a series of target proteins. Palmitoylation is a reversible post-translational modification involved in membrane protein trafficking between membranes and in their functional modulation. However, studies on the relationship between palmitoylation and calcium signaling have been limited. Here, we demonstrate that the yeast palmitoyl transferase ScAkr1p homolog, AkrA in Aspergillus nidulans, regulates [Ca2+]c homeostasis. Deletion of akrA showed marked defects in hyphal growth and conidiation under low calcium conditions which were similar to the effects of deleting components of the high-affinity calcium uptake system (HACS). The [Ca2+]c dynamics in living cells expressing the calcium reporter aequorin in different akrA mutant backgrounds were defective in their [Ca2+]c responses to high extracellular Ca2+ stress or drugs that cause ER or plasma membrane stress. All of these effects on the [Ca2+]c responses mediated by AkrA were closely associated with the cysteine residue of the AkrA DHHC motif, which is required for palmitoylation by AkrA. Using the acyl-biotin exchange chemistry assay combined with proteomic mass spectrometry, we identified protein substrates palmitoylated by AkrA including two new putative P-type ATPases (Pmc1 and Spf1 homologs), a putative proton V-type proton ATPase (Vma5 homolog) and three putative proteins in A. nidulans, the transcripts of which have previously been shown to be induced by extracellular calcium stress in a CrzA-dependent manner. Thus, our findings provide strong evidence that the AkrA protein regulates [Ca2+]c homeostasis by palmitoylating these protein candidates and give new insights the role of palmitoylation in the regulation of calcium-mediated responses to extracellular, ER or plasma membrane stress.
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences, Nanjing Normal University, Nanjing, China.
authors.forename: Yuanwei
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences, Nanjing Normal University, Nanjing, China.
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Zheng
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences, Nanjing Normal University, Nanjing, China.
authors.forename: Congcong
authors.initials: C
authors.lastname: Sun
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences, Nanjing Normal University, Nanjing, China.
authors.forename: Jinxing
authors.initials: J
authors.lastname: Song
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences, Nanjing Normal University, Nanjing, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Gao
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences, Nanjing Normal University, Nanjing, China.
authors.forename: Shizhu
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom.
authors.forename: Alberto
authors.initials: A
authors.lastname: Muñoz
authors.affiliation: Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom.
authors.forename: Nick D
authors.initials: ND
authors.lastname: Read
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences, Nanjing Normal University, Nanjing, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Lu
mesh_terms: D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism; D020816:Amino Acid Motifs / Q000235:genetics*; D000935:Antifungal Agents / Q000494:pharmacology; D001233:Aspergillus nidulans / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology*; D059865:Endoplasmic Reticulum Stress / Q000502:physiology; D025301:Hyphae / Q000235:genetics / Q000254:growth & development; D017136:Ion Transport / Q000235:genetics; D017964:Itraconazole / Q000494:pharmacology; D054878:Lipoylation; D013172:Spores, Fungal / Q000254:growth & development; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: D000935:Antifungal Agents; D014415:Tunicamycin; D017964:Itraconazole; D000217:Acyltransferases; D000251:Adenosine Triphosphatases; D002118:Calcium