Anion channel protein

Ashley RH. 2003. Challenging accepted ion channel biology p64 and the CLIC family of putative intracellular anion channel proteins. Mol Membr Biol 20 1-11. 

Yang Z, Schumaker EM, Egorin MJ, Zuhowski EG, Guo Z, 45. Cullen KJ. Cisplatin preferentially binds mitochondrial DNA and voltage-dependent anion channel protein in the mitochondrial membrane of head and neck squamous cell carcinoma possible... 

In the erythrocyte membrane, proteins such as ankyrin and the anion channel protein, help to link the membrane to the underlying intracellular backbone. 

Ankyrin is a peripheral membrane protein of the erythrocyte membrane (Figure 10.17). It functions to anchor the anion channel protein to the membrane skeleton (Figure 10.18, Table 10.5). 

See also Membrane Proteins, Erythrocyte Membrane, Passive Transport Mechanisms, Anion Channel Protein... 

Chloride channels are membrane proteins that allow for the passive flow of anions across biological membranes. As chloride is the most abundant anion under physiological conditions, these channels are often called chloride channels instead of anion channels, even though other anions (such as iodide or nitrate) may permeate better. As some CLC proteins function as CF-channels, whereas other perform CF/H+-exchangers are also mentioned here. 

Several different changes in mitochondria occur during apoptosis. These include a change in membrane potential (usually depolarization), increased production of reactive oxygen species, potassium channel activation, calcium ion uptake, increased membrane permeability and release of cytochrome c and apoptosis inducing factor (AIF) [25]. Increased permeability of the mitochondrial membranes is a pivotal event in apoptosis and appears to result from the formation of pores in the membrane the proteins that form such permeability transition pores (PTP) may include a voltage-dependent anion channel (VDAC), the adenine nucleotide translocator, cyclophilin D, the peripheral benzodiazepine receptor, hexokinase and... 

There are several hypotheses for a specific mechanism by which ONOO- can control the open state of the PTPC. Briefly the PTPC is regulated by primary constituents of the pore, including the inner membrane adenine nucleotide translocase (ANT) and the outer membrane protein voltage-dependent anion channel (VDAC or porin). The VDAC-ANT complex can bind to signaling proteins that modulate permeability transition, such as pro-apoptotic Bax (which opens the pore) and anti-apoptotic Bcl-2... 

Our model of cytochrome c release during apoptosis is not an alternative mechanism to the Bid/Bax-regulated release of cytochrome c. The voltage-dependent anion channel (VDAC) is known to be converted to a cytochrome c-permeant conduit by Bax. Furthermore, Bax protein can... 

SENSORY MECHANISM ionic differences at membrane pH, anion effects on membrane membrane penetration ion channel protein binding specific protein binding ion channel protein binding protein complexation generalized membrane interaction... 

One of the major integral proteins of the erythrocyte membrane is the anion channel, or band-3 protein, which moves Cl- and HC03 anions across the membrane. The anion transporter has two identical subunits with molecular weights of about 95,000, and each subunit probably has 10 or 11 transmembrane helices. The band-3 protein is attached to the spectrin cytoskeleton through a smaller protein, anky-rin. The cytosolic domain of the anion transporter also binds the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase. 

The structure of spectrin and the location of spectrin in the cytoskeleton. (a) An a/3 dimer of spectrin. Both a and f3 subunits are extended structures consisting of end-to-end domains of 106 amino-acyl residues folded into three a helices the subunits twist about one another loosely as shown. (b) The erythrocyte membrane skeleton. Spectrin tetramers ((X2P2), shown in yellow, are linked to the cytoplasmic domain of the anion channel (blue) by the protein ankyrin (red), and to glycophorin and actin filaments by protein 4.1. This structure lends stability to the red cell membrane while maintaining sufficient flexibility to allow erythrocytes to withstand substantial shear forces in the peripheral circulation. 

CaSR may also influence the proliferative and apoptotic status of the cells indirectly via modulation of cell volume homeostasis. Indeed, stimulation of CaSR in human epithelial cells induces upregulation of volume-regulated anion channels (VRAC) via a G protein-mediated increase in intracellular cAMP (Shimizu, et al., 2000). Proliferation and apoptosis are associated with essential volume perturbations [e.g., (Lang, et al., 2000)] and VRAC, a key component of homeostatic volume regulation, has been directly implicated in proliferation (Chen, et al., 2002, Doroshenko, et al., 2001, Shen, et al., 2000, Wang, et al., 2002) and apoptosis (Lemonnier, et al., 2004, Okada, et al., 2001, Okada, et al., 2006, Shen, et al., 2002). Consequently, extracellular Ca2+ may affect carcinogenesis via the CaSR-VRAC-cell volume links. The Ca2+ -permeable store-operated channel (SOC) is directly and functionally coupled to VRAC in an androgen-dependent LNCaP human prostate cancer epithelial cell line (Lemonnier, et al., 2002), evidence for another, CaSR-unrelated, potential mechanism for extracellular Ca2+ involvement in proliferative and apoptotic events. 

Alkali metal transport in biochemistry is a vital process in maintenance of cell membrane potentials of use, for example, in nerve signal transduction and is at the core of some of the early work on artificial ionophores that mimic natural ion carriers such as valinomycin. Ionophore mediated ion transport is much slower than transport through cation and anion ion channel proteins, however. 

ATP may be released by exocytosis from neurons, where it is co-stored in synaptic vesicles with other neurotransmitters (Bumstock 2004), and from astrocytes (Volknandt 2002). ATP is also released upon stimulation of membrane receptors or upon mechanical stimulation by mechanisms that mainly involve transporters of the ABC protein family or ATP-permeable anion channels (Bodin and Bumstock 2001). Under pathological conditions, massive release of ATP may occur upon damage of the cell membrane or cell lysis. 

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