Intracellular chloride channel <p>Chloride (Cl^-) channels are known to be present in the plasma andintracellular membranes of many cell types. Whilst the molecular identityof plasma membrane Cl^- channels has been known for some time, only recentlyhave intracellular Cl^- channels been characterised. Initially, a 64 kDaprotein was purified from solubilised kidney cortical membranes, which, whenreconstituted into phospholipid vesicles, gave rise to chloride channelactivity [<cite idref="PUB00006029"/>]. An antibody generated against this protein (p64) wassubsequently used to identify and clone it. The predicted amino acidsequence for p64 shows that it contains two, or possibly four, putativetransmembrane (TM) domains and a number of possible phosphorylation sites.Expression studies have revealed that it is targeted to intracellularorganelles, not the plasma membrane [<cite idref="PUB00006030"/>].</p><p>Subsequently, a number of homologous cDNAs have been identified, which,when expressed, give rise to Cl^- channels in the membranes of both cellnuclei and endoplasmic reticulum [<cite idref="PUB00006031"/>, <cite idref="PUB00006032"/>]. They do not show significantsequence similarity to the CLC family of plasma membrane voltage-gated Cl^-channels.</p>