Protein tyrosine phosphatase variants in human hereditary disorders and disease susceptibilities.

Reversible tyrosine phosphorylation of proteins is a key regulatory mechanism to steer normal development and physiological functioning of multicellular organisms. Phosphotyrosine dephosphorylation is exerted by members of the super-family of protein tyrosine phosphatase (PTP) enzymes and many play such essential roles that a wide variety of hereditary disorders and disease susceptibilities in man are caused by PTP alleles. More than two decades of PTP research has resulted in a collection of PTP genetic variants with corresponding consequences at the molecular, cellular and physiological level. Here we present a comprehensive overview of these PTP gene variants that have been linked to disease states in man. Although the findings have direct bearing for disease diagnostics and for research on disease etiology, more work is necessary to translate this into therapies that alleviate the burden of these hereditary disorders and disease susceptibilities in man.

Highly sensitive detection and mutational analysis of lung cancer circulating tumor cells using integrated combined immunomagnetic beads with a droplet digital PCR chip.

Circulating tumor cells (CTCs) have become an important biomarker for liquid biopsy to monitor tumor progression and indicate response to therapies. Many epithelial cellular adhesion molecule (EpCAM) dependent CTC isolation methods have been developed, which have a limitation for low EpCAM expressed tumor cells. In an effort to overcome these drawbacks, we developed combined immunomagnetic beads (EpCAM, Mucin1 and epidermal growth factor receptor) to sensitively isolate CTCs for immunofluorescence analysis and genetic characterization. With this combined immunomagnetic beads, 93.35% H446 cells from spiked blood sample can be recovered. We were able to detect CTCs in 127 among 143 patients included in the study (88.8%). Some CTC clusters were captured with the combined magnetic beads system. In 17 of them, CTCs after chemotherapy significantly decreased compared to that before chemotherapy (4.42 (±â€¯3.94) vs. 12 (±â€¯7)/mL, P = 0.002). For subsequent genetic characterization of CTCs, 2 of 6 samples, using a droplet digital PCR (ddPCR) chip, have detectable EGFR L858R mutation in the cells enriched with the combined immunomagnetic beads. In conclusion, this method integrating the combined immunomagnetic beads and the ddPCR chip for CTCs detection can be of potential application in terms of diagnosis, therapeutic evaluation and personalized medicine in lung cancer.

Epithelial junctions and Rho family GTPases: the zonular signalosome.

The establishment and maintenance of epithelial cell-cell junctions is crucially important to regulate adhesion, apico-basal polarity and motility of epithelial cells, and ultimately controls the architecture and physiology of epithelial organs. Junctions are supported, shaped and regulated by cytoskeletal filaments, whose dynamic organization and contractility are finely tuned by GTPases of the Rho family, primarily RhoA, Rac1 and Cdc42. Recent research has identified new molecular mechanisms underlying the cross-talk between these GTPases and epithelial junctions. Here we briefly summarize the current knowledge about the organization, molecular evolution and cytoskeletal anchoring of cell-cell junctions, and we comment on the most recent advances in the characterization of the interactions between Rho GTPases and junctional proteins, and their consequences with regards to junction assembly and regulation of cell behavior in vertebrate model systems. The concept of "zonular signalosome" is proposed, which highlights the close functional relationship between proteins of zonular junctions (zonulae occludentes and adhaerentes) and the control of cytoskeletal organization and signaling through Rho GTPases, transcription factors, and their effectors.