Cell Biology of Copper
The transition metal, copper (Cu), is an essential micronutrient for normal plant growth and development. Copper is a cofactor of proteins involved in photosynthesis, respiration, ethylene perception, removal of superoxide radicals, and cell wall modification. The biochemical reactions catalyzed by most Cu enzymes in plants are known. However, in many cases we are not yet sure about the biological function of these Cu proteins. Copper delivery to Cu proteins has evolved with a set of evolutionarily conserved transporters and metallo-chaperones. Analysis of Cu transporter and metallo-chaperone loss of function mutants has increased our understanding of the localization and biological function of many Cu delivery mechanisms and target Cu proteins. Studies examining the regulation of Cu transporters, metallo-chaperones, and Cu proteins have revealed an elegant system to regulate Cu homeostasis. Copper in excess is toxic while Cu deficiency can lead to decreased photosynthetic activity and reproductive success. To avoid Cu deficiency or toxicity symptoms in a sub-optimal environment, plants are capable of directing Cu delivery based on their needs via regulation of Cu proteins and delivery systems. For many Cu proteins, a network of Cu microRNAs, under the control of a SPL7 transcription factor, orchestrates the prioritization of Cu delivery based on Cu availability.
KeywordsAmine Oxidase Ethylene Receptor Ascorbate Oxidase Thylakoid Lumen Endomembrane System
Work in the author’s laboratory was supported by grants from the U.S. National Science Foundation to MP (NSF-IBN-0418993; NSF-IOS-0847442). We apologize to colleagues whose work could not be cited due to space limitations.
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