Expression and Localisation of Wave Isoforms in Human Schwann and Schwannoma Cells

Abstract

Schwannoma, the main tumours associated with Neurofibromatosis Type II, are caused by loss of function mutations in the NF2 gene, encoding for the tumour suppressor Merlin. Schwannoma cells display protrusive structures, due to deregulation of the cytoskeleton. The cytoskeleton is controlled by small Rho GTPases, such as Rac1 and Cdc42, known to be activated continuously in merlin-deficient human schwannoma cells (NF2-/-). Downstream Rac signalling leads to the activaton of Wave signalling complexes, which have been shown to bind and activate the Arp2/3 complex, a crucial regulator of the actin cytoskeleton that is involved in formation of protrusive structures. This investigation used an established NF2 model of primary human Schwann and schwannoma cells to investigate the expression and localisation of Pan-Wave and Wave-2. Using commercially available antibodies, immunocytochemistry (ICC) labelling for Pan-Wave showed an atypical distribution in both human Schwann and schwannoma cells. Western blotting for Pan-Wave in NF2-/- (schwannoma cells) also showed multiple non-specific bands. ICC for Wave2 in human schwannoma showed atypical distribution of this isoform. Western blotting for Wave2 using whole Schwann cell lysate, schwannoma lysate and HL60 cell lysate confirmed the non-specificity of the antibody. Therefore the specificity regarding commercially available antibodies is discussed.