CNG-modulin: a novel Ca-dependent modulator of ligand sensitivity in cone photoreceptor cGMP-gated ion channels.

The transduction current in several different types of sensory neurons arises from the activity of cyclic nucleotide-gated (CNG) ion channels. The channels in these sensory neurons vary in structure and function, yet each one demonstrates calcium-dependent modulation of ligand sensitivity mediated by the interaction of the channel with a soluble modulator protein. In cone photoreceptors, the molecular identity of the modulator protein was previously unknown.

Progesterone activates the principal Ca2+ channel of human sperm.

Steroid hormone progesterone released by cumulus cells surrounding the egg is a potent stimulator of human spermatozoa. It attracts spermatozoa towards the egg and helps them penetrate the egg's protective vestments. Progesterone induces Ca(2+) influx into spermatozoa and triggers multiple Ca(2+)-dependent physiological responses essential for successful fertilization, such as sperm hyperactivation, acrosome reaction and chemotaxis towards the egg.

Acid extrusion from human spermatozoa is mediated by flagellar voltage-gated proton channel.

Human spermatozoa are quiescent in the male reproductive system and must undergo activation once introduced into the female reproductive tract. This process is known to require alkalinization of sperm cytoplasm, but the mechanism responsible for transmembrane proton extrusion has remained unknown because of the inability to measure membrane conductance in human sperm. Here, by successfully patch clamping human spermatozoa, we show that proton channel Hv1 is their dominant proton conductance.

Phenotypic subpopulations of metastatic colon cancer stem cells: genomic analysis.

Background: Human cancer is characterized by high heterogeneity in gene expression, varieties of differentiation phenotypes and tumor-host interrelations. Growing evidence suggests that tumor-initiating, or cancer stem cells (CSCs), may also represent a heterogeneous population. The present study was undertaken to isolate and characterize the different phenotypic subpopulations of metastatic colon cancer and to develop a working colon CSC model for obtaining highly tumorigenic and clonogenic cells in sufficient numbers.

Clinical significance of telomerase activity in peritoneal disseminated cells: gastrointestinal cancers.

Early detection and accurate staging of gastrointestinal (GI) cancers are difficult. The aim of this study was to evaluate whether telomerase activity (TA) in exfoliated/disseminated epithelial cells could be used as a reliable marker for GI cancers. TA was evaluated with the real-time RTQ-TRAP in immunomagnetically sorted peritoneal epithelial cells from 60 patients undergoing surgical treatment.