11 - Inorganic Polyphosphate: A Novel, Global, and Very Effective Chaperone
University of Michigan
Molecular, Cellular, and Developmental Biology
To function properly, proteins need to be folded in a certain way. To make sure proteins are properly folded, cells must maintain a favorable internal environment. If the internal conditions deviate from this favorable environment, such as by heating cells, proteins begin to unfold, or denature. These unfolded proteins then begin to clump together, or aggregate, leading to diseases (e.g. Alzheimer€s) or cell death. Our lab has discovered that inorganic polyphosphate (polyP), a molecule which has been around since before dawn of life, protects proteins against aggregation. In one experiment we showed that polyP protects the majority of proteins in a cell against aggregation, showing that polyP protects a wide range of proteins. We also found that polyP works both under heat-denaturing conditions and under chemical-denaturing conditions, meaning that polyP works under a range of conditions. Next we showed that longer chains of polyP are more efficient at protecting proteins than shorter chains of polyP. Taken together, our results show that polyP effectively protects a wide range of proteins against aggregation. This is of great significance since polyP may have been involved in the making of the first forms of life.