 |
The images shown are arranged in triplets, stained with immunofluorescent
markers for GpIb alpha (red), an unrelated platelet adhesion protein, GPIIb/IIIa
(green) with the superimposition of both these images shown on the right.
The top triplet shows normal doner platelets stained to show surface-expressed
proteins. Below that is a triplet of normal doner platelets treated
(permeabilized) to allow detection of intracellular proteins. Next are platelets
from a Bernard Soulier patient (AKK) stained for exterior proteins. The bottom
panel shows permeabilized BSS platelets. Note: The BSS platelets do
not express GpIb alpha on the surface of their platelets but express ample
amounts of this protein in their cytoplasm. The BSS defect in this platelet
has been identified as a point mutation leading to a premature stop signal
in the transcription of GpIb beta. Thus it appears that the function of the
GpIb beta protein is to transport or maintain the GpIb alpha protein in the
platelet membrane. |