A Gate Hinge Controls the Epithelial Calcium Channel TRPV5.

TRPV5 is unique within the large TRP channel family for displaying a high Ca selectivity together with Ca-dependent inactivation. Our study aims to uncover novel insights into channel gating through in-depth structure-function analysis. We identify an exceptional tryptophan (W583) at the terminus of the intracellular pore that is unique for TRPV5 (and TRPV6).

Urinary β-galactosidase stimulates Ca2+ transport by stabilizing TRPV5 at the plasma membrane.

Transcellular Ca(2+)transport in the late distal convoluted tubule and connecting tubule (DCT2/CNT) of the kidney is a finely controlled process mediated by the transient receptor potential vanilloid type 5 (TRPV5) channel. A complex-type-N-glycan bound at the extracellular residue Asn358 of TRPV5 through post-translational glycosylation has been postulated to regulate the activity of TRPV5 channels. Using in vitro Ca(2+)transport assays, immunoblot analysis, immunohistochemistry, patch clamp electrophysiology and total internal reflection fluorescence microscopy, it is demonstrated that the glycosidase β-galactosidase (β-gal), an enzyme that hydrolyzes galactose, stimulates TRPV5 channel activity.

The epithelial calcium channel TRPV5 is regulated differentially by klotho and sialidase.

The transient receptor potential vanilloid type 5 (TRPV5) Ca(2+) channel facilitates transcellular Ca(2+) transport in the distal convoluted tubule (DCT) of the kidney. The channel is glycosylated with a complex type N-glycan and it has been postulated that hydrolysis of the terminal sialic acid(s) stimulate TRPV5 activity. The present study delineates the role of the N-glycan in TRPV5 activity using biochemical assays in Human Embryonic Kidney 293 cells expressing TRPV5, isoelectric focusing and total internal reflection fluorescent microscopy.

A modular and noncovalent transduction system for leucine-zipper-tagged proteins.

Modes of transport: A leucine-zipper-tagged GFP was transported into cells by "zipping" it (red) to it's complementary leucine zipper (blue) functionalized with a cell-penetrating peptide (CPP). This transport system has an inherent modularity as the CPP is "clicked" to the leucine zipper, and then noncovalently bound to the protein, thus making it system particularly useful for targeting studies.

Fast production of homogeneous recombinant RNA--towards large-scale production of RNA.

In the past decades, RNA molecules have emerged as important players in numerous cellular processes. To understand these processes at the molecular and atomic level, large amounts of homogeneous RNA are required for structural, biochemical and pharmacological investigations. Such RNAs are generally obtained from laborious and costly in vitro transcriptions or chemical synthesis.