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Defective actin polymerization in EBV‐transformed B‐cell lines from patients with the Wiskott–Aldrich syndrome
Author(s) -
Facchetti Fabio,
Blanzuoli Laura,
Vermi William,
Notarangelo Luigi D.,
Giliani Silvia,
Fiorini Maurilia,
Fasth Anders,
Stewart Donn M.,
Nelson David L.
Publication year - 1998
Publication title -
the journal of pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.964
H-Index - 184
eISSN - 1096-9896
pISSN - 0022-3417
DOI - 10.1002/(sici)1096-9896(199805)185:1<99::aid-path48>3.0.co;2-l
Subject(s) - wiskott–aldrich syndrome protein , wiskott–aldrich syndrome , actin , cytoskeleton , biology , immunocytochemistry , actin cytoskeleton , microbiology and biotechnology , western blot , cell , gene , genetics , endocrinology
The Wiskott–Aldrich syndrome (WAS) is a rare X‐linked recessive disorder characterized by eczema, thrombocytopenia, and immunodeficiency. An allelic variant of the disease is characterized by isolated thrombocytopenia (XLT). The gene responsible for WAS/XLT (WASP) encodes for a 502 amino acid protein (WASP) that is possibly involved in actin binding and cytoskeleton organization. The expression of WASP and the distribution of F‐actin and alpha‐actinin (which binds to and stabilizes actin filaments) have been analysed in lymphoblastoid cell lines from six patients with WAS and one with XLT. Western blot and immunocytochemistry did not reveal WASP expression in four WAS patients, whereas two WAS patients (with a moderate clinical course) expressed trace amounts of mutant WASP. In contrast, the XLT patient expressed normal amounts of WASP. Furthermore, cell lines from WAS and XLT patients also markedly differed in F‐actin polymerization and alpha‐actinin distribution. In particular, severe defects of cytoplasmic F‐actin expression and of F‐actin‐positive microvillus formation, and impaired capping of alpha‐actinin, were observed in all patients who lacked WASP. As a whole, the degree of impairment of WASP protein expression in WAS/XLT seems to correlate with anomalies of cytoskeletal organization, strongly supporting a role for WASP in the regulation of F‐actin polymerization. © 1998 John Wiley & Sons, Ltd.