Stanford University School of Medicine scientists working in part at SSRL's
Beam Line 11-1 have uncovered new molecular insights to the mechanism behind
immune disorders such as asthma. Using protein x-ray crystallography at 3.0
Angstrom resolution, researchers Sherry LaPorte and Chris Garcia solved three
structures of two signaling proteins known as "cytokines" in complex with their
shared receptors, where these molecules help regulate immune system activity.
The study was published as the cover story in the January 25 edition of
the journal Cell.
Cytokines are a family of proteins and peptides responsible for transmitting
information from cell to cell by binding with special receptors on cell
surfaces. In the current study, Garcia and colleagues worked out three
structures involving two separate cytokines-interleukin-4 (IL-4) and
interleukin-13 (IL-13), which are associated with allergic asthma. Although
both have very different signaling effects, IL-4 and IL-13 are known to bind
with some of the same receptors.
The study revealed that, despite sharing common receptors, very different
chemistries underlie the binding activities of IL-4 and IL-13, a feature that
may play a direct role in immune system disorders such as asthma. The discovery
could lead to future drug therapies that address these differences and help
down-regulate the immune response that results in the life-threatening risks
associated with an asthma attack.
Sherry L. LaPorte, Z. Sean Juo, Jana Vaclavikova, Leremy A. Colf, Xiulan Qi,
Nicola M. Heller, Achsah D. Keegan and K. Christopher Garcia (2008). "Molecular
and Structural Basis of Cytokine Receptor Pleiotropy in the Interleukin-4/13
System" Cell 132(2): 259-272.
To learn more about this research see the full scientific highlight at:
http://www-
ssrl.slac.stanford.edu/research/highlights_archive/IL-4.html