The E3 ubiquitin ligase CHIP (C‐terminus of Hsc70‐interacting protein) is believed to be a central player in the cellular triage decision, as it links the molecular chaperones Hsp70/Hsc70 and Hsp90 to the ubiquitin proteasomal degradation pathway. To better understand the decision process, we determined the affinity of CHIP for Hsp70 and Hsp90 using isothermal titration calorimetry. We analyzed the influence of CHIP on the ATPase cycles of both chaperones in the presence of co‐chaperones and a substrate, and determined the ubiquitination efficacy of CHIP in the presence of the chaperones. We found that CHIP has a sixfold higher affinity for Hsp90 compared with Hsc70. CHIP had no influence on ADP dissociation or ATP association, but reduced the Hsp70 cochaperone Hdj1‐stimulated single‐turnover ATPase rates of Hsc70 and Hsp70. CHIP did not influence the ATPase cycle of Hsp90 in the absence of co‐chaperones or in the presence of the Hsp90 cochaperones Aha1 or p23. Polyubiquitination of heat‐denatured luciferase and the native substrate p53 was much more efficient in the presence of Hsc70 and Hdj1 than in the presence of Hsp90, indicating that CHIP preferentially ubiquitinates Hsp70‐bound substrates.Structured digital abstract MINT‐7904367: CHIP (uniprotkb:Q9UNE7) and HSP 90‐beta (uniprotkb:P08238) physically interact (MI:0915) by molecular sieving (MI:0071) MINT‐7904785: HSP 90‐beta (uniprotkb:P08238) and p23 (uniprotkb:Q15185) bind (MI:0407) by molecular sieving (MI:0071) MINT‐7904047: CHIP (uniprotkb:Q9UNE7), HSP 90‐beta (uniprotkb:P08238) and p23 (uniprotkb:Q15185) physically interact (MI:0915) by molecular sieving (MI:0071) MINT‐7903424: Alpha‐lactalbumin (uniprotkb:P00711), HSP70 (uniprotkb:P08107) and CHIP (uniprotkb:Q9UNE7) physically interact (MI:0915) by molecular sieving (MI:0071) MINT‐7903354: CHIP (uniprotkb:Q9UNE7) and HSC70 (uniprotkb:P11142) bind (MI:0407) by isothermal titration calorimetry (MI:0065) MINT‐7903373: CHIP (uniprotkb:Q9UNE7) and HSP90‐beta (uniprotkb:P08238) bind (MI:0407) by isothermal titration calorimetry (MI:0065)
It has already been proven that trees and shrubs, can efficiently remove particulate matter (PM) from air. However, almost nothing is known about PM accumulation by herbaceous plants (grasses and forbs) found in urban meadows. Meadows, unlike trees and shrubs, can be located close to roads, one of the main sources of PM in cites. The aim of this study was to investigate the tolerance to urban condition and PM accumulation in the immediate roads vicinity of selected plants species in urban meadows. PM accumulation of annual and perennial meadows was compared with that of lawns. Results were interpreted in the context of species composition, biomass production, soil conditions and ambient PM concentrations. Of the species grown in annual meadows, the highest PM accumulation was found in Achillea millefolium L., Chenopodium album L. and Echium vulgare L., while Centaurea scabiosa L., Echium vulgare L. and Convolvulus arvensis L. accumulated the largest amounts of PM in perennial meadows. PM deposition on plants was positively correlated with a feathery leaf shape. For species in the annual meadows, a positive correlation was also found between PM accumulation and the wax content on plants. The presence of hairs on leaves, leaf size and plant growth pattern had no effect on PM deposition on plants. PM accumulation in one square metre of urban meadow was on average greater than that of lawn, regardless of meadow species' composition, age and location. The greatest accumulation of PM was found in a perennial meadow with low biodiversity but the greatest biomass. It would appear that the biomass produced by meadows and canopy structure has a crucial impact on the amount of PM accumulated by meadow plants. The results obtained indicate that meadows could be an important element of nature-based solutions for mitigating air pollution in urbanised areas.