Researchers at the Massachusetts Institute of Technology, working with colleagues at Southwestern Medical Center in Dallas, said the protein molecule that binds to high-density lipoprotein cholesterol, the «good cholesterol,» proved to be one that had been previously known but was believed to have had other functions.
The long-sought molecule, or «cell-surface receptor,» is a protein known as SR-B1, the researchers said in a report being published on Friday in the journal Science. Tests with mice and rats indicated that the molecule not only binds with high-density lipoprotein, or H.D.L., cholesterol, but also influences the transfer of cholesterol to specific tissues that need it to make steroid hormones.
«No one has ever had a well-defined H.D.L. receptor until now,» said Dr. Monty Krieger of M.I.T., the project’s senior researcher. «We know almost nothing about how H.D.L. is metabolized in the body and this should prove to be a valuable tool for this kind of research.»
