Short PLUNC1 (SPLUNC1) is the founding member of a novel family of proteins (PLUNC) expressed in the upper respiratory tract that may function in host defence. It is one of the most highly expressed genes in the upper airways and the protein has been detected in sputum and nasal secretions. This study describes, for the first time, the precise cellular localization of SPLUNC1 in human tissues from the respiratory tract. Although SPLUNC1 is found in some epithelial cells of the upper airways and coats the surface epithelial cell lining of the major airways, the most significant site of protein localization is in mucous cells and ducts of submucosal glands. Intense staining is also seen in minor glands of the nose, sinuses, posterior tongue and tonsil, suggesting that the protein is secreted into mucoid secretions of these tissues, where it probably functions in host defence. No staining was seen in peripheral lung tissue. As SPLUNC1 has been suggested to be a novel lung cancer marker, a limited panel of lung cancers was also studied. The findings suggest that SPLUNC1 is commonly expressed in adenocarcinomas, muco-epidermoid carcinoma, and bronchio-alveloar carcinoma, and is absent from small-cell carcinoma and squamous cell carcinoma. This expression pattern is consistent with the presumed phenotypic origin of these tumours and suggests that SPLUNC1 may be a useful marker for lung cancer.

These studies indicate that although syk may play an important role in mediating degranulation, the relative level of syk expression does not govern human lung mast cell releasability. Identification of the mechanisms that govern IgE-dependent activation of human lung mast cells is likely to be of wider clinical significance, given the central role that mast cells play in the development of allergic asthma.

Asthma is a chronic inflammatory lung disease with considerable unmet medical needs for new and effective therapies. Cytosolic phospholipase A 2 ␣ (cPLA 2 ␣) is the rate-limiting enzyme that is ultimately responsible for the production of eicosanoids implicated in the pathogenesis of asthma. We investigated a novel cPLA 2

We report a technique for isolation and solubilization of intermediate filament (IF) proteins from colonic biopsies compatible with both gel electrophoresis and liquid chromatography "shotgun" proteomics using mass spectrometry (MS). This is important because changes in the IF proteome, particularly in keratin expression and modification, are noted in colonic mucosa of patients with colorectal cancer. Though keratins have traditionally been dissolved in high concentration of urea, the latter solvent precludes efficient proteolytic digestion by trypsin prior to gel-free LC-MS/MS approaches. The extraction of cytoskeletal proteins was initially evaluated using MCF-7 cancer cell lines using a published, differential detergent solubilization protocol. IF proteins were extracted from colonic biopsies using a combination of homogenization and sonication. Since comparable efficiency of solubilization was noted on the extracted IF from cell lines between urea and guanidine hydrochloride (GuHCl) in triethylammonium bicarbonate buffer, isolated proteins from endoscopic biopsies were solubilized in GuHCl. Using immunoblotting techniques, we successfully demonstrated isolation of keratins and preservation of posttranslational modifications (phosphorylation, acetylation). Dissolved proteins were tryptically digested and peptides analyzed by MS, showing the functionality of the workflow in shotgun proteomic applications, specifically compatibility of the workflow for isobaric tagging relative and absolute quantification based quantitation approaches.