10 Dec 2002

Researchers from the biotechnology company SUGEN (a subsidiary of Pharmacia Corporation) and the Salk Institute in La Jolla, California, report that they have mapped all 518 protein kinases in the human genome. In the December 6 Science, they describe some of the features of this catalogue of enzymes.

Rather than the 1,000 kinases predicted some 15 years ago by coauthor Tony Hunter, there appear to be only about half that many in the human genome. This number still represents about 1.7 percent of all human genes and reflects the significance of these enzymes for most biological processes-it is estimated that kinases control as much as 30 percent of protein activity.

Of the kinases identified, 71 had not been previously reported or described as kinases. In addition, the study corrects the protein sequences of 56 known kinases. Of the newly identified kinases, many belong to previously described families, but several appear to constitute new families. The vast majority (478) of the 518 kinases belong to the superfamily of eukaryotic protein kinases, whereas 40 are termed "atypical protein kinases" because they act as kinases but have structural differences from the larger family.

"We had a clear computational strategy for how to mine the human genome for protein kinases. And yet, we didn't solely rely on automation. We manually went through each one of these sequences to confirm that the mapping process was accurate," said author Sucha Sudarsanam of Pharmacia in a news release from the Salk Institute.

A number of kinase genes have already been studied in relation to Alzheimer's disease (see Alzforum gene compendium), and this complete catalogue will undoubtedly prove useful in some of the many strands of Alzheimer’s research.—Hakon Heimer