Dynamic reorganization of metabolic enzymes into intracellular bodies.
Both focused and large-scale cell biological and biochemical studies have revealed that hundreds of metabolic enzymes across diverse organisms form large intracellular bodies. These proteinaceous bodies range in form from fibers and intracellular foci--such as those formed by enzymes of nitrogen and carbon utilization and of nucleotide biosynthesis--to high-density packings inside bacterial microcompartments and eukaryotic microbodies. Although many enzymes clearly form functional mega-assemblies, it is not yet clear for many recently discovered cases whether they represent functional entities, storage bodies, or aggregates. In this article, we survey intracellular protein bodies formed by metabolic enzymes, asking when and why such bodies form and what their formation implies for the functionality--and dysfunctionality--of the enzymes that comprise them. The panoply of intracellular protein bodies also raises interesting questions regarding their evolution and maintenance within cells. We speculate on models for how such structures form in the first place and why they may be inevitable.
Center for Systems and Synthetic Biology, University of Texas, Austin, Texas 78712, USA.
Jeremy D
JD
O'Connell
Alice
A
Zhao
Andrew D
AD
Ellington
Edward M
EM
Marcotte
D000818:Animals; D003594:Cytoplasmic Granules / Q000201:enzymology* / Q000378:metabolism / Q000648:ultrastructure; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure; D029968:Escherichia coli Proteins / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D006801:Humans; D053858:Metabolic Networks and Pathways; D020675:Peroxisomes / Q000201:enzymology; D020836:Protein Structure, Quaternary; D021381:Protein Transport; D015003:Yeasts / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure
D029968:Escherichia coli Proteins; D005656:Fungal Proteins