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Sodium-Calcium Exchangers (NCX1-3
& NCKX1-2) & Ca+-Pump Antibodies
Ca2+ plays a critical role in intracellular
signaling. Intracellular Ca2+ levels are tightly controlled by continuos removal
of Ca2+ via ATP-driven Ca2+ pump in the endoplasmic reticulum and plasma
membrane, and Ca2+ transport system, the Na+/Ca2+ exchangers (NCX), in the
plasma membrane. NCX can move Ca2+ either into or out of cells, depending on the
net Na+, Ca2+, and K+ gradient across the membrane. In most cells, 3 Na+ are
exchanged for 1 Ca2+. In mammals, at least 5 distinct genes code for the
exchangers: Three NCX (NCX1, NCX2, and NCX3), and two in the NCKX family (NCKX1
and NCKX2). NCX share significant sequence homology (~70%), display 11 TM
domains, a large central, intracellular hydrophilic regulatory loop between TM5
and 6, extracellular N-terminus and cytoplasmic C-terminus. The N-terminal
signal peptide is cleaved off from the mature exchanger protein.
NCX contains a highly basic region in the large hydrophilic, intracellular loop
called XIP (Exchange inhibitory peptide; RRLLFYKYVYKRYRAGKQRG 20 aa), that
inhibits Na-Ca+ exchange in cardiac sarcolemmal vesicles and in other cells.
Little or no sequence identity is found between the NCX and the Ca-pump.
However, XIP also inhibits the Ca pumps with more or less same efficiency as
C28R2 peptide sequence (LRRGQILWFRGLNRIQTQIRVVKAFRSS, 28 aa) corresponding to
the autoinhibitory domain of the Ca-pump.
NCX1 (rat 971 aa, human 970 aa, mouse 970 aa) is most prominently expressed in
the heart where it plays a major role in excitation-contraction coupling, but is
also present in most other tissues. Alternative spicing of NCX1/NACA1 produces
numerous tissue specific isoforms (heart NACA1; Kidney NACA2, -3, and -7; brain
NACA4-6). NCX2 (rat 921 aa) is restricted to brain and skeletal muscle. NCX3
(rat 927 aa) shares 73-75% with NCX1 and NCX2. It is predicted to have the same
membrane topology as NCX1. Like NCX2, NCX3 is restricted to brain and muscle.
In vertebrate photoreceptors, some neurons, and certain other cells, 3 K+ are
transported in the same direction as Ca2+, with coupling ratio of 4 Na+ to 1
Ca2+ plus 1 K+ by new class of exchangers called NCKX for K+-dependent Na/Ca+2
exchangers. NCKX share the general topology and functional properties of NCX
proteins. Rod exchangers also contains a large hydrophilic segment at the its
N-terminus that is not found in NCX. NCKX1 (human 1099/1081 aa, bovine 1199 aa)
is expressed in retinal rod cells. NCKX2 (rat 670 aa) shares 80% identity with
NCKX1. The two hydrophilic loops are also much shorter in NKKX2 than in NCKX1,
accounting largely for the difference between the size of the two proteins.
NCKX2 is expressed in various regions of the brain (striatum, parietal cortex,
cerebellum, hippocampus, and thalamus).
ADI has produced highly specific rabbit antibodies to NCX1-3, NCKX1-2, and also
to the XIP and C28R2 using peptide sequences specific to each protein.
|
Items |
Antigen
peptide location |
Antibody
Host |
Ab
Crossreactivity |
Antiserum
Cat #
(100 ul) |
Aff.
Pure IgG
Cat #
(100 ug) |
* Control
Peptide Cat#
(100 ug) |
|
NCX1 (Ab#1) |
r, 18 aa ~EC1 |
Rb |
r, m (h, rb?) |
NCX11-S |
NCX11-A |
NCX11-P |
|
NCX1 (Ab#2) |
r, 23 aa ~CP3 |
Rb |
r, m, h, rb |
NCX12-S |
NCX12-A |
NCX12-P |
|
NCX2 |
r, 22 aa ~CP3 |
Rb |
r |
NCX21-S |
NCX21-A |
NCX21-P |
|
NCX3 |
r, 20 aa ~EC1 |
Rb |
r |
NCX31-S |
NCX31-A |
NCX31-P |
|
XIP |
r, 20 aa, XIP |
Rb |
m, r, h |
XIP11-S |
XIP11-A |
XIP11-P |
|
C28R2/Ca+-ATPase (Ab#1)
|
r, 28 aa, CP6, C28R2
|
ch
|
m, r, h
|
C28R21-S
|
. |
C28R21-P
|
|
Ca+-ATPase (Ab#2)
|
r, 20 aa, CP2
|
Rb
|
m, r, h
|
PMCA21-S
|
PMCA21-A
|
PMCA21-P
|
|
Ca+-ATPase (Ab#3)
|
H, Purified Eryth. ATPase
|
m,
mono
|
m, r, h
|
PMCA31-M
|
|
MSHB21-P
|
|
NCKX1
|
h, 21 aa ~EC1
|
Rb
|
h, b
|
NCKX11-S
|
NCKX11-A
|
NCKX11-P
|
|
NCKX1 (Ab#2) |
r, 15aa,
~NT, EC |
Rb |
m, r |
NCKX12-S |
NCKX12-A |
NCKX12-P |
m=mouse; r=rat; h=human; ch=chicken; f=frog; ~CT or ~NT=near
C or N-terminus. EC=Extracellular; CP=Cytoplasmic domain;
"Neat Antisera" are
the unpurified antiserum and it is suitable for ELISA
and Western.
"Affinity pure"
antibodies have been over the antigen-affinity
column and recommended for immunohistochemical
applications.
"Control peptides"
can not be used for Western as they are very short
peptides. They are intended for ELISA or antibody
competition studies.
List
of publications
using ADI's Antibodies to various NCXs related items
Product Authors Year of Pub Title Journal Western IHC IP
Other tech Comments
C28R2
Zhong, Ning 2001 Roles for Mitochondrial and Reverse
Mode Na+/Ca2+ Exchange and the Plasmalemma Ca2+ ATPase
in Post-Tetanic Potentiation at Crayfish Neuromuscular
Junctions,J. Neurosci. 21: 9598-9607, peptides
CASR
Wang R, 2003, Calcium and polyamine regulated
calcium-sensing receptors in cardiac tissues Eur. J.
Biochem., Jun 2003; 270: 2680 - 2688, WB, IHC , rat
mycocytes
NCX1
Unlap MT 2003 Na+/Ca2+ Exchanger. Target for Oxidative
Stress in Salt-Sensitive Hypertension Hypertension, 42,
363-368 WB OK-pth cells
NCX1
Okafor M 2003 Sodium-calcium exchange influences the
response to endothelin-1 in lens epithelium Cell Calcium
34, Issue 3, September 2003, Pages 231-240 WB IHC 4% PF
,Bovine eye lens, Ab blocking with CP
XIP
Zhong, Ning 2001 Roles for Mitochondrial and Reverse
Mode Na+/Ca2+ Exchange and the Plasmalemma Ca2+ ATPase
in Post-Tetanic Potentiation at Crayfish Neuromuscular
Junctions, J. Neurosci. 21: 9598-9607, peptides
Notes: Antibodies usage is
indicated in the following techniques:
WB=Western
Blot ; IHC-Immunohistochmistry;
IP=Immunoprecipition;
Flow=Flow
cytometry
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