Linked Life Data

17006516

Source:http://linkedlifedata.com/resource/pubmed/id/17006516

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7110
pubmed:dateCreated
2006-9-28
pubmed:abstractText
P-type ATPase pumps generate concentration gradients of cations across membranes in nearly all cells. They provide a polar transmembrane pathway, to which access is strictly controlled by coupled gates that are constrained to open alternately, thereby enabling thermodynamically uphill ion transport (for example, see ref. 1). Here we examine the ion pathway through the Na+,K+-ATPase, a representative P-type pump, after uncoupling its extra- and intracellular gates with the marine toxin palytoxin. We use small hydrophilic thiol-specific reagents as extracellular probes and we monitor their reactions, and the consequences, with cysteine residues introduced along the anticipated cation pathway through the pump. The distinct effects of differently charged reagents indicate that a wide outer vestibule penetrates deep into the Na+,K+-ATPase, where the pathway narrows and leads to a charge-selectivity filter. Acidic residues in this region, which are conserved to coordinate pumped ions, allow the approach of cations but exclude anions. Reversing the charge at just one of those positions converts the pathway from cation selective to anion selective. Close structural homology among the catalytic subunits of Ca2+-, Na+,K+- and H+,K+-ATPases argues that their extracytosolic cation exchange pathways all share these physical characteristics.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1476-4687
pubmed:author
pubmed:issnType
Electronic
pubmed:day
28
pubmed:volume
443
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
470-4
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Ion permeation through the Na+,K+-ATPase.
pubmed:affiliation
Laboratory of Cardiac/Membrane Physiology, The Rockefeller University, New York, New York 10021, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural