Linked Life Data

21721517

Source:http://linkedlifedata.com/resource/pubmed/id/21721517

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
32
pubmed:dateCreated
2011-8-9
pubmed:abstractText
ABCA4 is a photoreceptor-specific ATP-binding cassette transporter implicated in the clearance of all-trans-retinal produced in the retina during light perception. Multiple mutations in this protein have been linked to Stargardt disease and other visual disorders. Here we report the first systematic study of posttranslational modifications in native ABCA4 purified from bovine rod outer segments. Seven N-glycosylation sites were detected in exocytoplasmic domains 1 and 2 by mass spectrometry, confirming the topological model of ABCA4 proposed previously. The modifying oligosaccharides were relatively short and homogeneous, predominantly representing a high-mannose type of N-glycosylation. Five phosphorylation sites were detected in cytoplasmic domain 1, with four of them located in the linker "regulatory-like" region conserved among ABCA subfamily members. Contrary to published results, phosphorylation of ABCA4 was found to be independent of light. Using human ABCA4 mutants heterologously expressed in mammalian cells, we showed that the Stargardt disease-associated alanine mutation in the phosphorylation site at position 901 led to protein misfolding and degradation. Furthermore, replacing the S1317 phosphorylation site reduced the basal ATPase activity of ABCA4, whereas an alanine mutation in either the S1185 or T1313 phosphorylation site resulted in a significant decrease in the all-trans-retinal-stimulated ATPase activity without affecting the basal activity, protein expression, or localization. In agreement with this observation, partial dephosphorylation of native bovine ABCA4 led to reduction of both basal and stimulated ATPase activity. Thus, we present the first evidence that phosphorylation of ABCA4 can regulate its function.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1520-4995
pubmed:author
pubmed:issnType
Electronic
pubmed:day
16
pubmed:volume
50
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6855-66
pubmed:dateRevised
2011-11-2
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Posttranslational modifications of the photoreceptor-specific ABC transporter ABCA4.
pubmed:affiliation
Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106, United States.
pubmed:publicationType
Journal Article