N-WASP has the ability to compensate for the loss of WASP in macrophage podosome formation and chemotaxis.
Wiskott-Aldrich syndrome protein (WASP) and its homologue neural-WASP (N-WASP) are nucleation promoting factors that integrate receptor signaling with actin cytoskeleton rearrangement. While hematopoietic cells express both WASP and N-WASP, WASP deficiency results in altered cell morphology, loss of podosomes and defective chemotaxis. It was determined that cells from a mouse derived monocyte/macrophage cell line and primary cells of myeloid lineage expressed approximately 15-fold higher levels of WASP relative to N-WASP. To test whether N-WASP can compensate for the loss of WASP and restore actin cytoskeleton integrity, N-WASP was overexpressed in macrophages, in which endogenous WASP expression was reduced by short hairpin RNA (shWASP cells). Many of the defects associated with the loss of WASP, such as podosome-dependent matrix degradation and chemotaxis were corrected when N-WASP was expressed at equimolar level to that of the wild-type WASP. Furthermore, the ability of N-WASP to partially compensate for the loss of WASP may be physiologically relevant since activated murine WASP-deficient peritoneal macrophages, which show enhanced N-WASP expression, also show an increase in matrix degradation. Our study suggests that expression levels of WASP and N-WASP may influence their roles in actin cytoskeleton rearrangement and shed light to the complex intertwining roles WASP and N-WASP play in macrophages.
Isaac
Beth M
BM
Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA. bisaac@wesleyan.edu
Ishihara
Dan
D
Nusblat
Leora M
LM
Gevrey
Jean-Claude
JC
Dovas
Athanassios
A
Condeelis
John
J
Cox
Dianne
D
D000818:Animals; D019556:COS Cells; D045744:Cell Line, Tumor; D048430:Cell Shape / Q000235:genetics; D002633:Chemotaxis / Q000187:drug effects / Q000235:genetics; D002522:Chlorocebus aethiops; D003713:Dendritic Cells / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D015870:Gene Expression / Q000235:genetics; D008262:Macrophage Activation / Q000276:immunology; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology* / Q000378:metabolism*; D017737:Macrophages, Peritoneal / Q000276:immunology / Q000378:metabolism; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011554:Pseudopodia / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D013864:Thioglycolates / Q000276:immunology; D014162:Transfection; D051316:Wiskott-Aldrich Syndrome Protein / Q000235:genetics / Q000378:metabolism*; D051300:Wiskott-Aldrich Syndrome Protein Family / Q000378:metabolism; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal / Q000235:genetics / Q000378:metabolism*
D005353:Fibronectins; D013864:Thioglycolates; C495768:Was protein, mouse; C492303:Wasf2 protein, mouse; C495772:Wasl protein, mouse; D051316:Wiskott-Aldrich Syndrome Protein; D051300:Wiskott-Aldrich Syndrome Protein Family; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D016173:Macrophage Colony-Stimulating Factor