GATA-1, G208S macrothrombocytes are deficient in talin: immunofluorescence studies.

Previous investigations from our laboratory identified the ultrastructural pathology and cytochemistry of macrothrombocytes (MTC) from patients with the X-linked, G208S varient of the GATA-1 mutation.A subsequent biochemical study of the MTC cytoskeletal proteins using polyacrylamide gel electrophoresis and western blot analysis revealed the MTC were deficient in the high-molecular weight, actin binding protein, talin. The present study has used immunofluorescent techniques to further characterize the talin deficiency. Results confirm that the GATA-1, G208S MTC are deficient in talin, and what little is present relocates to the undersurface of the plasma membrane following activations where it associates with adhesion plaques.

Cytoskeletons of X-linked GATA-1, G208S macrothrombocytes are deficient in talin.

An X-linked mutation in the GATA-1 transcription factor, G208S, causes macrothrombocytopenia and serious bleeding problems in affected male family members. The unique ultrastructural pathology of their platelets was described previously. The present investigation has evaluated the cytoskeletal proteins of the GATA-1, G208S macrothrombocytes of two male patients by page gel electrophoresis and Western blot analysis. The 235-245 KD cytoskeletal protein, Talin, was absent from their (PAGE) gels and undetectable by a specific talin antibody on Western blots.

Alpha-delta platelet storage pool deficiency in three generations.

Alpha-Delta platelet storage pool deficiency (alphadelta SPD) is a rare inherited bleeding disorder affecting both males and females, occurring in families, as well as sporadically. Patient platelets in most cases are moderately deficient in both alpha granules and dense bodies. Only one patient has been severely deficient in both organelles. The present study is the first to document a severe decrease in both platelet alpha granules and dense bodies in four members in three generations of the same family. Efforts to differentiate this disorder from other hypogranular platelets syndromes in the present investigation suggested that the alpha granules and dense bodies become connected to channels of the open canalicular system (OCS) and lose their contents to the exterior without prior activation of the cells. In contrast, alpha granule formation in the white platelet syndrome is too slow, and cells leave the bone marrow still in the process of producing organelles. Gray platelet syndrome platelets can make alpha granules, but their enclosing membranes are unable to retain stored products. As a result, the organelles lose their contents to surrounding cytoplasm in megakaryocytes and platelets, not selectively through the demarcation system channels and OCS channels. Thus, the pathogenesis of alphadelta SPD is unique.