Does the phosphorylation of MAP65-1 correlate with the effects of Cr(VI) on Arabidopsis thaliana microtubules?

{"title":"Does the phosphorylation of MAP65-1 correlate with the effects of Cr(VI) on Arabidopsis thaliana microtubules?","authors":"Ioannis-Dimosthenis S. Adamakis,&nbsp;Eleftherios P. Eleftheriou","doi":"10.1007/s11738-024-03765-2","DOIUrl":null,"url":null,"abstract":"<div><h3>Key message</h3><p>MAP65-1 phosphorylation mediates Cr(VI)-induced microtubule disruption in plants.</p><h3>Abstract</h3><p>Chromium (Cr) exists in two prevalent forms in the environment: trivalent Cr(III) and hexavalent Cr(VI). While Cr(III) can benefit plants as a micronutrient, Cr(VI) is highly toxic and disrupts essential physiological, biochemical, and cellular processes in plants. Plant cell microtubules (MTs) are particularly susceptible to Cr(VI) toxicity, with MAP65-1, a key microtubule-associated protein, playing a crucial role in stabilizing MTs by forming cross-bridges between them. The stability function of MAP65-1 is influenced by its phosphorylation status: phosphorylation causes MAP65-1 to detach from MTs during different cell cycle phases. This study investigated how Cr(VI) affects MAP65-1 presence on cortical MTs in <i>Arabidopsis thaliana</i> roots and hypocotyls. Seedlings expressing GFP:AtMAP65-1 and its non-phosphorylatable variant, AtMAP65-1^9A (GFP:AtMAP65-1^9A), were exposed to 100 μM potassium dichromate (K₂Cr₂O₇, Cr(VI)) on ½ MS solid medium for 24 or 48 h. Confocal laser scanning microscopy (CLSM) revealed that Cr(VI) began impacting cortical MTs within 24 h. The signal intensity of GFP indicated a significant reduction in MAP65-1 presence, whereas the GFP:AtMAP65-1^9A signal remained stable and MTs were unaffected. These results suggest that Cr(VI) toxicity to MTs is linked to MAP65-1’s phosphorylation status.</p></div>","PeriodicalId":6973,"journal":{"name":"Acta Physiologiae Plantarum","volume":"47 2","pages":""},"PeriodicalIF":2.4000,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11738-024-03765-2.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Acta Physiologiae Plantarum","FirstCategoryId":"99","ListUrlMain":"https://link.springer.com/article/10.1007/s11738-024-03765-2","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"PLANT SCIENCES","Score":null,"Total":0}