Hi, I'm Linda Hendershot,
The Department of Tumor Cell Biology at
St. Jude Children's Research Hospital in Memphis, Tennessee.
I'll be talking about the chaperon systems of the endoplasmic reticulum.
The ability of cells to communicate with each other and their environment in
specific ways is essential to survival in multicellular organisms.
One of the primary ways this is done is through proteins
expressed on the cell surface or secreted from the cell.
For example, a damaged cell or tumor cell,
which requires additional nutrients or oxygen,
has the ability to secrete pro-angiogenic factors which will bind to
endothelial cells and stimulate the production of
blood vessel and oxygen flow to the tumor cell.
Another example is direct cell to cell communication.
For example, a virus-infected cell is recognized by
a T-cell of the immune system by an antigen is expressed on the cell surface,
which can induce the T-cells to kill the virus-infected cell.
Another example is the secretion of effector molecules like antibodies from plasma cells,
which can target bacteria for destruction.
Another example is the use of proteins for cellular communication can be seen
in the migration of cells throughout the body or homing into specific tissues.
For example, a B cell,
which can be synthesized in the fetal liver or in the bone marrow,
was turned to a lymph node,
which occurs at the expression of proteins on
the B cell surface that interacts with proteins on the surface of the lymph node.
The cell surface and secreted proteins are