Organotins block a cell's protein recycling center.

Dec 15, 2008

Shi, G, D Chen, Z Guangshu, MS Chen, QC Cui, Q Zhau, B He, QP Dou and G Jiang.  2008.  The proteasome is a molecular target of environmental toxic organotinsEnvironmental Health Perspectives.  doi:10.1289/ehp.11865.

Widely-used pollutants called organotins can harm cells - and even kill them - by interfering with their ability to take apart unwanted proteins.

In this important study, Chinese scientists describe precisely how organotins may exert their toxic effects in cells. They found that the chemicals bind to and block the activity of a key cell molecule -- called the proteasome -- making it dysfunctional.

The proteasome is critical for breaking down and recycling unneeded or damaged proteins.  This newly discovered way that organotins affect cells helps explain some of the adverse health effects observed in wildlife and in animal studies.

Organotins, such as triphenyltin and tributyltin, are widely used as antifouling additives in boat paint, antifungal agents for textiles and industrial water systems and as agricultural pesticides.  Exposure to organotins has been linked to adverse health effects including cancer, altered reproductive development and neurotoxicity. 

Another organotin, dibutyltin, is linked to increased allergic reactions, inflammation and  asthma and also to obesity.  This molecule is widely used in PVC plastics.

Because the proteasome is so critical for breaking down unwanted proteins in the cell, blocking it lets these proteins build up and, essentially, gum up the machinery of the cell.  The organotin-proteasome interaction can also lead to cell death.