Voltage-gated Na(+) channels (NaV channels) are specifically blocked by guanidinium toxins such as tetrodotoxin (TTX) and saxitoxin (STX) with nanomolar to micromolar affinity depending on key amino acid substitutions in the outer vestibule of the channel that vary with NaV gene isoforms. All NaV channels that have been studied exhibit a use-dependent enhancement of TTX/STX affinity when the ch...

Scorpion venom is rich in proteinaceous toxins that affect excitability by impeding ion channel gating. Channel blockers interact with the external region of the pore and obstruct ion conductance, whereas channel modifiers interact with the voltage sensor module hindering the activation or inactivation processes [1-3]. Scorpion toxin modifiers of voltage-gated sodium channels (Navs) are divided...

Cystic fibrosis (CF) is a lethal disease caused by mutations in the chloride channel CFTR gene. The disease is characterized by decreased chloride secretion and unregulated sodium absorption through the epithelial sodium channel (ENaC) in the airway epithelium and other affected organs. We hypothesize that a non-CFTR alternative chloride channel ClCN2 can be activated to negatively regulate ENa...

The cystic fibrosis transmembrane conductance regulator (CFTR) gene encodes a chloride channel protein that belongs to the superfamily of ATP binding cassette (ABC) transporters. Phosphorylation by protein kinase A in the presence of ATP activates the CFTR-mediated chloride conductance of the apical membranes. We have identified a novel hydrophilic CFTR binding protein, CAP70, which is also con...

Cystic fibrosis (CF) affects approximately 1 in 2000 people making it one of the commonest fatal, inherited diseases in the Caucasian population. CF is caused by mutations in a cyclic AMP-regulated chloride channel known as CFTR, which is found on the apical plasma membrane of many exocrine epithelial cells. In the CF pancreas, dysfunction of the CFTR reduces the secretory activity of the tubul...

For vertebrate olfactory signal transduction, a calcium-activated chloride conductance serves as a major amplification step. However, the molecular identity of the olfactory calcium-activated chloride channel (CaCC) is unknown. Here we report a proteomic screen for cilial membrane proteins of mouse olfactory sensory neurons (OSNs) that identified all the known olfactory transduction components ...

Description: BOTOX COSMETIC (Botulinum Toxin Type A) Purified Neurotoxin Complex is a sterile, vacuum-dried purified botulinum toxin type A, produced from fermentation of Hall strain Clostridium botulinum type A grown in a medium containing casein hydrolysate, glucose and yeast extract. It is purified from the culture solution by dialysis and a series of acid precipitations to a complex consist...

Dendrotoxin proteins isolated from Mamba snake venom block potassium channels with a high degree of specificity and selectivity. Using site-directed mutagenesis we have identified residues that constitute the functional interaction surfaces of delta-dendrotoxin and its voltage-gated potassium channel receptor. delta-Dendrotoxin uses a triangular patch formed by seven side-chains (Lys3, Tyr4, Ly...

A defect in the yeast GEF1 gene, a CLC chloride channel homolog leads to an iron requirement and cation sensitivity. The iron requirement is due to a failure to load Cu2+ onto a component of the iron uptake system, Fet3. This process, which requires both Gef1 and the Menkes disease Cu2+-ATPase yeast homolog Ccc2, occurs in late- or post-Golgi vesicles, where Gef1 and Ccc2 are localized. The def...

The existence of a large conductance voltage sensitive chloride channel is documented in undifferentiated cells (myoblasts) of the L6 rat muscle cell line. At this stage of development the resting membrane conductance is dominated by potassium ions only (Kidokoro 1975). The conductance of the channel in symmetrical 120 mmol/l choline chloride is 331 +/- 4 pS. The probability of the channel bein...