Evidence for the plant‐specific intercellular transport of the Arabidopsis copper chaperone CCH

• Published in: The Plant journal : for cell and molecular biology 2001-03, Vol.25 (5), p.521-528
• Main Authors: Mira, Helena, Martínez‐García, Fernando, Peñarrubia, Lola
• Format: Article
• Language: English
• Subjects: Arabidopsis - cytology; Arabidopsis - metabolism; ATX1‐homologue; Biological and medical sciences; Biological Transport; Blotting, Northern; CCH; Cellular Senescence; Copper - metabolism; copper homeostasis; Fundamental and applied biological sciences. Psychology; Homeostasis; Immunohistochemistry; metallochaperone; Molecular Chaperones - genetics; Molecular Chaperones - metabolism; Molecular Sequence Data; phloem transport; Plant Leaves - anatomy & histology; Plant Leaves - metabolism; Plant physiology and development; RNA, Plant - analysis; senescence; Water and solutes. Absorption, translocation and permeability
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1046/j.1365-313x.2001.00985.x

Summary Arabidopsis copper chaperone (CCH) belongs to a family of eukaryotic proteins that participates in intracellular copper homeostasis by delivering this metal to the secretory pathway. In this work we show that the CCH protein is mainly located along the vascular bundles of senescing leaves and petioles, as shown by tissue prints and immunohistochemical detection. CCH protein also accumulates in stem sieve elements and is collected in phloem exudates. Accordingly, Arabidopsis CCH is the only member of the metallochaperone family described to function intercellularly to date. Moreover, the CCH protein remains stable when plants are subjected to excess copper that causes a rapid and specific decrease in its mRNA. These facts point to a role for CCH in copper mobilization from decaying organs towards reproductive structures, as a result of metalloprotein breakdown.