Identification of SNARE and cell trafficking regulatory proteins in the salivary glands of the lone star tick, Amblyomma americanum (L.)

Abstract

Prostaglandin E 2 (PGE 2) stimulates secretion of tick salivary gland proteins via a phosphoinositide signaling pathway and mobilization of intracellular Ca 2+ ( Qian et al., 1998; Yuan et al., 2000). Highly conserved intracellular SNARE (soluble NSF attachment protein receptors) complex proteins are associated with the mechanism of protein secretion in vertebrate and invertebrate neuronal and non-neuronal cells. Proteins in the salivary glands of partially fed female lone star ticks cross-react individually with antibodies to synaptobrevin-2 (vesicle (v)-SNARE), syntaxin-1A, syntaxin-2 and SNAP-25 (target (t)-SNAREs), cytosolic α/β SNAP and NSF ( N-ethylmaleimide-sensitive fusion protein), Ca 2+ sensitive synaptotagmin, vesicle associated synaptophysin, and regulatory cell trafficking GTPases Rab3A and nSec1. V-SNARE and t-SNARE proteins form an SDS-resistant, boiling sensitive core complex in the salivary glands. Antibodies to SNARE complex proteins inhibit PGE 2-stimulated secretion of anticoagulant protein in permeabilized tick salivary glands. We conclude that SNARE and cell trafficking regulatory proteins are present and functioning in the process of PGE 2-stimulated Ca 2+ regulated protein secretion in tick salivary glands.