Unidirectional Na+, Ca2+, and K+ fluxes through the bovine rod outer segment Na-Ca-K exchanger.
نویسندگان
چکیده
منابع مشابه
Na-Ca or Na-Ca-K exchange in rod photoreceptors.
Remarkably dynamic Ca z ÷ fluxes control Ca 2 ÷ homeostasis in the outer segments of vertebrate rod photoreceptors (ROS). Ca 2 ÷ fluxes are believed to be carried by only two different membrane proteins embedded in the ROS plasma membrane; these two proteins as well as some of the other main molecular components of ROS are schematically depicted in Fig. 1. ROS are the sites of the process of vi...
متن کاملEffect of potassium ions and membrane potential on the Na-Ca-K exchanger in isolated intact bovine rod outer segments.
Two recent studies reported that Na-Ca exchange in the outer segments of tiger salamander rod photoreceptors (Cervetto, L., Lagnado, L., Perry, R. J., Robinson, D. W., and McNaughton, P. A. (1989) Nature 337, 740-743) and of bovine rod photoreceptors (Schnetkamp, P. P. M., Basu, D. K., and Szerencsei, R. T. (1989) Am. J. Physiol. 257, C153-157) requires and transports K+ in a 4Na/(1Ca+1K) stoic...
متن کاملThe topology of the C-terminal sections of the NCX1 Na+/Ca2+ exchanger and the NCKX2 Na+/Ca2+-K+ exchanger
Mammalian Na (+) /Ca ( 2+) (NCX) and Na (+) /Ca ( 2+) -K (+) exchangers (NCKX) are polytopic membrane proteins that play critical roles in calcium homeostasis in many cells. Although hydropathy plots for NCX and NCKX are very similar, reported topological models for NCX1 and NCKX2 differ in the orientation of the three C-terminal transmembrane segments (TMS). NCX1 is thought to have 9 TMS and a...
متن کاملThe Na+/Ca2+, K+ exchanger 2 modulates mammalian cone phototransduction
Calcium ions (Ca(2+)) modulate the phototransduction cascade of vertebrate cone photoreceptors to tune gain, inactivation, and light adaptation. In darkness, the continuous current entering the cone outer segment through cGMP-gated (CNG) channels is carried in part by Ca(2+), which is then extruded back to the extracellular space. The mechanism of Ca(2+) extrusion from mammalian cones is not un...
متن کاملNa+-dependent inactivation of the retinal cone/brain Na+/Ca2+-K+ exchanger NCKX2.
The SLC24 gene family Na+/Ca2+-K+ exchangers (NCKX) are bidirectional plasma membrane transporters whose main function is the extrusion of Ca2+ from the cytosol. In this study, we used human embryonic kidney 293 cells expressing human retinal cone/brain NCKX2 to examine its Na+ affinity and kinetic parameters of Ca2+ transport. With the use of the ionophore gramicidin to control alkali cation c...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1991
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(18)52421-2