Identification of MAL2, a novel member of the MAL proteolipid family, though interactions with TPD52-like proteins in the yeast two-hybrid system
GENOMICS
Authors: Wilson, SHD; Bailey, AM; Nourse, CR; Mattei, MG; Byrne, JA
Abstract
The TPD52 (tumor protein D52)-like proteins are small coiled-coil motif-bearing proteins which were first identified though their expression in human breast carcinoma. TPD52-like proteins are known to interact in hetero- and homomeric fashions, but there are no known heterologous binding partners for these proteins. We now report the cloning of a novel member of the MAL proteolipid family, named MAL2, though its interaction with a TPD52L2 bait in a yeast two-hybrid screen. MAL2 is predicted to be 176 residues (19 kDa) with four transmembrane domains and is 35.8% identical to MAL, a proteolipid required in apical vesicle transport. The MAL2 prey bound all TPD52-like baits tested in the yeast two-hybrid system and in vitro translation of MAL2 produced a single 19-kDa S-35-labeled protein which specifically bound full-length GST-Tpd52 in GST pull-down assays. The gene MAL2, which was localized to human chromosomal band 8q23 and shown to consist of four exons, is predominantly expressed in human kidney, lung, and liver. Our study has therefore identified a novel member of the MAL proteolipid family and potentially implicates TPD52-like proteins in vesicle transport.
Data independent acquisition-mass spectrometry (DIA-MS)-based comprehensive profiling of bone metastatic cancers revealed molecular fingerprints to assist clinical classifications for bone metastasis of unknown primary (BMUP)
TRANSLATIONAL CANCER RESEARCH
Authors: Ku, Xin; Cai, Chunlin; Xu, Yan; Chen, Su; Zhou, Zhenhua; Xiao, Jianru; Yan, Wei
Abstract
Background: Bone metastasis is the third most common metastatic cancers worldwide. It is a group of highly heterogeneous diseases with various potential cancer primaries. Among them, one third was diagnosed as bone metastasis of unknown primary (BMUP) due to lack of indication for the primary tumor even after comprehensive examinations. Thus, the prognosis of BMUP is often very poor since the treatment was largely empirical and untargeted. To assist identification of the primary tumor, a series of molecular markers including traditional tissue-specific histochemistry as well as gene and mRNA markers were developed with moderate to good sensitivity and specificity. Methods: In this paper, we carried out a comprehensive expression profiling for fresh-frozen tissue samples of bone metastasis from lung, prostate and liver cancers using high resolution, data-independent-acquisition mass spectrometry (DIA-MS). The proteome variation was analyzed and protein classifiers were prioritized. Results: Over 6,000 proteins were quantified from 18 samples, which, to the best of our knowledge, was never achieved before. Further statistical analysis and bioinformatics data mining revealed 4 significant proteins (RFIP1, CK15, ESYT2, and MAL2) with excellent discriminating capabilities with AUCs higher than 0.8. Conclusions: The comprehensive proteome map of bone metastases will complement available genomic and transcriptomic data. Newly discovered protein classifiers will expand current diagnostic arsenal for tissue of origin studies in BMUP. Furthermore, the proteome map generated in this study by DIA-MS allows future data re-mining as our knowledge advances to assist investigation of bone metastasis and progression of tumors as well as the development of diagnostic tools and prognosis management for BMUPs.