identifier: traitmech:000015 label: cobalt tolerant definition: A metal tolerance in which an organism grows in the presence of elevated cobalt (Co2+) concentrations, typically via cation-efflux resistance systems such as the czc and cnr determinants. definition_source: PMID:12829273 trait_category: ENVIRONMENT term_kind: CLASS mapping_status: REVIEWED parent_traits: - traitmech:000012 evidence: - reference: DOI:10.1111/j.1365-2958.2009.06792.x snippet: CzcP exports transition metals Zn(2+), Cd(2+) and Co(2+) notes: The cobalt-zinc-cadmium (czc) efflux system of Cupriavidus metallidurans confers cobalt resistance. - reference: DOI:10.3389/fmicb.2020.00047 snippet: C. metallidurans BS1 conferred resistance to Zn2+ displaying a MIC of 20 mM, Cd2+ (2.5 mM), Co2+ (20mM), Ni2+ (8 mM), As3+ (3.5 mM), Cu2+ (5 mM), Au3+ (1 uM) and Pb2+ (1.7 mM) notes: 'Organism example: Cupriavidus metallidurans BS1 tolerates cobalt to a MIC of 20 mM.' canonical_examples: - taxon_id: NCBITaxon:119219 taxon_label: Cupriavidus metallidurans note: "cobalt-resistance determinants" reference: PMID:20463976 causal_graphs: - graph_id: cobalt_tolerance_czc_cnr_efflux title: Cobalt tolerance via czc/cnr cation-efflux systems description: Evidence-backed causal sketch linking the czc and cnr efflux determinants to cytoplasmic cobalt detoxification. nodes: - node_id: cobalt_tolerant_trait label: cobalt tolerant node_type: TRAIT grounding: traitmech:000015 description: Capacity to grow at elevated Co(2+) concentrations. - node_id: cobalt_ion label: cobalt(2+) ion node_type: CHEMICAL grounding: CHEBI:48828 description: Toxic transition-metal cation accumulating in the cytoplasm. - node_id: cobalt_efflux_system label: czc/cnr cobalt efflux system node_type: GENE_OR_PROTEIN description: CzcCBA/CzcP and Cnr pumps exporting cobalt cations. - node_id: cobalt_export label: cobalt ion transmembrane transport node_type: BIOLOGICAL_PROCESS grounding: GO:0030001 description: Active export of Co(2+) across the cytoplasmic membrane. - node_id: czcCBA_complex label: CzcCBA efflux complex node_type: GENE_OR_PROTEIN description: HME-RND/CBA chemiosmotic divalent-cation/proton antiporter exporting Co2+, Zn2+, Cd2+. - node_id: czcRS_two_component label: CzcS/CzcR two-component system node_type: GENE_OR_PROTEIN description: Sensor kinase CzcS and response regulator CzcR that transcriptionally activate czcCBA. - node_id: czcCBA_expression label: czcCBA operon expression node_type: BIOLOGICAL_PROCESS description: Transcription of the czcCBA efflux operon. - node_id: cnr_operon label: cnr (cnrCBAYXHT) determinant node_type: GENE_OR_PROTEIN description: Cobalt-nickel resistance operon on plasmid pMOL28 conferring Co/Ni efflux. - node_id: dmeF_exporter label: DmeF CDF-family exporter node_type: GENE_OR_PROTEIN description: Cation diffusion facilitator with cobalt as preferred substrate. - node_id: rcnA_exporter label: RcnA/YohM Co/Ni efflux protein node_type: GENE_OR_PROTEIN description: Membrane-bound efflux system conferring nickel and cobalt resistance. - node_id: cobalt_homeostasis label: cellular cobalt homeostasis node_type: BIOLOGICAL_PROCESS description: Baseline management of cytoplasmic cobalt levels, including under non-stress conditions. edges: - subject: cobalt_ion predicate: challenges object: cobalt_tolerant_trait description: Cytoplasmic cobalt is the toxic challenge the trait counters. evidence: - reference: DOI:10.3389/fmicb.2020.00047 notes: Cupriavidus metallidurans BS1 tolerates Co(2+) to a MIC of 20 mM. predicate_id: METPO:2007406 - subject: cobalt_efflux_system predicate: enables object: cobalt_export description: CzcP exports cobalt together with zinc and cadmium cations. evidence: - reference: DOI:10.1111/j.1365-2958.2009.06792.x notes: CzcP exports transition metals Zn(2+), Cd(2+), and Co(2+). predicate_id: RO:0002327 - subject: cobalt_export predicate: mitigates object: cobalt_ion description: Czc/cnr-mediated export depletes the cytoplasmic cobalt pool. evidence: - reference: DOI:10.1111/j.1365-2958.2009.06792.x notes: The czc efflux system of C. metallidurans confers cobalt resistance. predicate_id: METPO:2007407 - subject: czcCBA_complex predicate: exports object: cobalt_ion description: CzcCBA RND antiporter effluxes cytoplasmic cobalt together with Zn2+ and Cd2+. evidence: - reference: DOI:10.3390/ijms26125716 notes: CzcCBA, an RND-superfamily chemiosmotic divalent cation/proton antiporter, deals with the efflux of Cd2+, Zn2+, and Co2+. predicate_id: METPO:2000209 - subject: czcRS_two_component predicate: activates transcription of object: czcCBA_expression description: CzcS sensor kinase activates response regulator CzcR, which transcriptionally activates czcCBA. evidence: - reference: DOI:10.3390/ijms26125716 notes: Activated CzcR functions as a transcriptional activator of czcCBA expression. - subject: czcCBA_expression predicate: enables object: cobalt_export description: Expression of the czcCBA operon produces the efflux complex enabling cobalt export. evidence: - reference: DOI:10.3390/ijms26125716 notes: czcCBA encodes the CzcCBA system mediating Co2+ efflux. predicate_id: RO:0002327 - subject: cnr_operon predicate: confers resistance to object: cobalt_tolerant_trait description: The cnrCBAYXHT operon confers cobalt (and nickel) resistance. evidence: - reference: DOI:10.1007/s44274-025-00301-y notes: This strain exhibits resistance to 3 mM Ni and 5 mM Co, conferred by the cnrCBAYXHT operon located on plasmid pMOL28. - subject: dmeF_exporter predicate: exports object: cobalt_ion description: DmeF CDF-family exporter preferentially effluxes cobalt. evidence: - reference: DOI:10.1007/s44274-025-00301-y notes: Co2+ is the preferred substrate for the DmeF protein in Cupriavidus metallidurans CH34. predicate_id: METPO:2000209 - subject: rcnA_exporter predicate: enables object: cobalt_export description: RcnA/YohM is an efflux system for nickel and cobalt, increasing cobalt resistance. evidence: - reference: DOI:10.1128/JB.187.8.2912-2916.2005 notes: yohM encodes a membrane-bound polypeptide conferring increased nickel and cobalt resistance in E. coli; YohM is the first described efflux system for nickel and cobalt in E. coli. predicate_id: RO:0002327 - subject: cobalt_export predicate: contributes to object: cobalt_homeostasis description: Czc/Cnr efflux complexes are present even without added metals, contributing to baseline cobalt homeostasis as well as stress resistance. evidence: - reference: DOI:10.1093/mtomcs/mfae058 notes: Czc-CBA proteins were also present in control cells cultivated without added metals so that Czc has also a function in metal homeostasis. predicate_id: RO:0002326 curation_history: - timestamp: '2026-05-28T00:00:00Z' curator: claude action: PROPOSED_FROM_RESEARCH changes: Proposed candidate ENVIRONMENT trait (cobalt tolerance) from literature research; metal-specific sub-variant of metal tolerant. llm_assisted: true - timestamp: '2026-06-09T14:00:00Z' curator: claude action: CURATED_CAUSAL_GRAPH changes: Added evidence-backed causal graph (czc/cnr cobalt efflux) with CHEBI/GO node groundings and RO/METPO predicate groundings; promoted PROPOSED to REVIEWED. llm_assisted: true - timestamp: '2026-06-23T00:00:00Z' curator: claude action: ENRICH_CAUSAL_GRAPH changes: Added 7 evidence-backed generic edges (7 new nodes) from the deep-research report. llm_assisted: true - timestamp: '2026-06-24T17:21:09Z' curator: claude action: GROUND_CAUSAL_PREDICATES changes: Grounded 5 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (METPO:2000209×2, RO:0002327×2, RO:0002326×1). llm_assisted: true