Faculty Member Christopher D. Lima

Memorial Sloan-Kettering Cancer Center researchers have uncovered the structure of a network of proteins that help regulate the life cycle of cells. Structural biologist Christopher D. Lima led the study, which used x-ray crystallography to identify how one protein, called small ubiquitin-related modifier (SUMO-1), joins with three other molecules. Understanding the network's layout is an important step toward learning how SUMO regulates its assembly and function.

The complex, described in the June 2 issue of Nature, includes SUMO-1, a molecule to which SUMO is attached (the substrate), and two other proteins, called E2 and E3. E2 links SUMO to target molecules, while E3 draws E2 and the substrate together. [PubMed Abstract]

"Understanding this process broadens our understanding of many physiological steps that are misregulated in cancer -- including error-prone DNA replication, chromosome segregation, and the cell's response to stress," Dr. Lima said.

Previous research has implicated SUMO in the normal assortment of chromosomes immediately before a cell divides. Yeast cells lacking SUMO cannot successfully divide. Since cancer cells divide unchecked, studying SUMO's function may yield insights into cancer and anticancer therapies.

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