The Nobel Assembly at Karolinska Institutet in Stockholm, Sweden, has awarded the Nobel Prize in Physiology or Medicine for 1999 to Gunter Blobel, for the discovery that "proteins have intrinsic signals that govern their transport and localization in the cell."

A large number of proteins carrying out essential functions are constantly being made within our cells. These glycoproteins have to be transported either out of the cell, or to different compartments - the organelles - within the cell. How are newly made proteins transported across the membrane surrounding the organelles, and how are they directed to their correct location?

These questions have been answered through the work of the 1999 Nobel Laureate in Physiology or Medicine, Dr. Günter Blobel, a cell and molecular biologist at the Rockefeller University in New York. Already at the beginning of the 1970s he discovered that newly synthesized glycoproteins have an intrinsic signal that is essential for governing them to and across the membrane of the endoplasmic recticulum, one of the cell's organelles. During the next twenty years, Blobel characterized in detail the molecular mechanisms underlying these processes. He also showed that similiar "address tags", or "zip codes," direct glycoproteins to other intracellular organelles.

The principles discovered and described by Günter Blobel turned out to be universal, operating similarly in yeast, plant, and animal cells. A number of human hereditary diseases are caused by errors in these signals and transport mechanisms. Blobel's research has also contributed to the development of more effective use of cells as "protein factories" for the production of important drugs.

Glyconutrients, comprised of the eight essential biological sugars, are essential in the formation of these glycoproteins within our cells. They support the process our individual tissue cells use to recognize and communicate properly with each other. The work of Dr. Blobel and many others have led to our recent understanding of the importance of good cell to cell communication for ensuring optimal health. The discovery of the role that glyconutrients play in human health has now entered mainstream medicine.

While Dr. Blobel has continued to study cell to cell communication, so have other researchers worldwide. Forthcoming "synthetic drugs" based on these essential sugars, which will most likely be toxic and have side effects, are years away in development. However, one does not have to wait until these drugs arrive in order to enjoy the health benefits of supplementing with natural forms of these glyconutrients. Dr. Emil Mondoa explains, "these eight essential sugars, known as saccharides, are the basis of multicellular intelligence -- the ability of cells to communicate, cohere, and work together to keep us healthy and balanced. Even tiny amounts of these sugars -- or lack of them -- have profound effects."

Dr. Günter Blobel, born in 1936, works at the Laboratory of Cell Biology at The Rockefeller University in New York. His research has led to better understanding of the intracellular protein synthesis and transport processes pertaining to the functions of the organelles and other microstructures found within cells.

Listen to a previously recorded PBS Newshour interview between Dr. Blobel and Newsmaker Gwen Ifill:

Just as a letter is routed through the postal system using Zip Codes, glycoproteins incorporate similiar unique identifiers in their molecular structures which assist in their transport. A glycoprotein consists of a protein molecule bound to a complex carbohydrate structure consisting of any number of molecular combinations and arrangements of the eight essential monosaccharides. The large number of combinations of these sugars comprises an "address", or a unique identifying code which is believed to direct and facillitate protein transportation.

How do newly synthesized proteins find their correct destinations within a cell, and how are they able to pass across the tightly sealed intracellular membranes? These were the central questions that Günter Blobel began to address in the late 1960s. He started by analyzing now newly synthesized secretory proteins are first targeted to and then translocated across the membrane of the endoplasmic reticulum. These two steps are prerequisites for secretion of proteins out of the cell.

The diagram above shows a view of protein translocation across the endoplasmic recticulum membrane. The signal peptide, emerging from the ribosome, binds to the signal-recognition particle (SRP). The SRP-ribosome complex then docks to the SRP-receptor and channel ("translocon"). SRP dissociates from the receptor and the nascent polypeptide chain is translocated through the channel into the endoplasmic recticulum lumen. The signal peptide is finally cleaved and the protein is secreted out of the cell.

In 1980 Blobel proposed that newly made proteins are targeted to and imported into the various organelles within the cell by built-in signal sequences. The signals are short stretches of amino acids encoded by the gene specifying the protein. They can be located at either end of the protein, or somewhere internally.