Summary
Platelets are dynamic cell fragments that modify their shape during activation. Utrophin
and dystrophins are minor actin-binding proteins present in muscle and non-muscle
cytoskeleton. In the present study, we characterised the pattern of Dp71 isoforms
and utrophin gene products by immunoblot in human platelets. Two new dystrophin isoforms
were found, Dp71f and Dp71d, as well as the Up71 isoform and the dystrophin-associated
proteins, α and β-dystrobrevins. Distribution of Dp71d/Dp71Δ110
m , Up400/Up71 and dystrophin-associated proteins in relation to the actin cytoskeleton
was evaluated by confocal microscopy in both resting and platelets adhered on glass.
Formation of two dystrophin-associated protein complexes (Dp71d/Dp71Δ110
m ~DAPC and Up400/Up71~DAPC) was demonstrated by co-immunoprecipitation and their distribution
in relation to the actin cytoskeleton was characterised during platelet adhesion.
The Dp71d/Dp71Δ110
m ~DAPC is maintained mainly at the granulomere and is associated with dynamic structures
during activation by adhesion to thrombin-coated surfaces. Participation of both Dp71d/Dp71Δ110
m ~DAPC and Up400/Up71~DAPC in the biological roles of the platelets is discussed.
Keywords Actin structures - adhesion - cytoskeleton - dystrophin-associated protein complexes
- platelet activation