| Literature References | 1. REDHEAD, C.R., EDELMAN, A.E., BROWN, D., LANDRY, D.W. AND AL-AWQATI, Q.
A ubiquitous 64kDa protein is a component of a chloride channel of plasma
and intracellular membranes.
PROC.NATL.ACAD.SCI.U.S.A. 89 3716-3720 (1992).
2. LANDRY, D.W., SULLIVAN, S., NICOLAIDES, M., REDHEAD, C., EDELMAN, A.,
FIELD, M., AL-AWQATI, Q. AND EDWARDS, J.
Molecular cloning and characterization of p64, a chloride channel protein
from kidney microsomes.
J.BIOL.CHEM. 268 14948-14955 (1993).
3. VALENZUELA, S.M., MARTIN, D.K., POR, S.B., ROBBINS, J.M., WARTON, K.,
BOOTCOV, M.R., SCHOFIELD, P.R., CAMPBELL, T.J. AND BREIT, S.N.
Molecular cloning and expression of a chloride channel ion channel of cell
nuclei.
J.BIOL.CHEM. 272 12575-12582 (1997).
4. DUNCAN, R.R., WESTWOOD, P.K., BOYD, A. AND ASHLEY, R.H.
Rat brain P64H1, expression of a new member of the p64 chloride channel
protein family in endoplasmic reticulum.
J.BIOL.CHEM. 272 23880-23886 (1997).
|
| Documentation | Chloride (Cl-) channels are known to be present in the plasma and
intracellular membranes of many cell types. Whilst the molecular identity
of plasma membrane Cl- channels has been known for some time, only recently
have intracellular Cl- channels been characterised. Initially, a 64 kDa
protein was purified from solubilised kidney cortical membranes, which, when
reconstituted into phospholipid vesicles, gave rise to chloride channel
activity [1]. An antibody generated against this protein (p64) was
subsequently used to identify and clone it. The predicted amino acid
sequence for p64 shows that it contains two, or possibly four, putative
transmembrane (TM) domains and a number of possible phosphorylation sites.
Expression studies have revealed that it is targeted to intracellular
organelles, not the plasma membrane [2].
Subsequently, a number of homologous cDNAs have been identified, which,
when expressed, give rise to Cl- channels in the membranes of both cell
nuclei and endoplasmic reticulum [3,4]. They do not show significant
sequence similarity to the CLC family of plasma membrane voltage-gated Cl-
channels.
INTCLCHANNEL is a 5-element fingerprint that provides a signature for
intracellular chloride channels. The fingerprint was derived from an
initial alignment of 3 sequences: the motifs were drawn from conserved
regions from the N-terminal 2/3 of the alignment - motif 1 resides within
the single putative TM domain; and motifs 2-5 lie in the cytoplasmic
C-terminal domain. Two iterations on SPTR37_10f were required to reach
convergence, at which point a true set comprising 6 sequences was
identified.
|