Journal article
Demonstration of Phosphoryl Group Transfer Indicates That the ATP-binding Cassette (ABC) Transporter Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Exhibits Adenylate Kinase Activity
The Journal of biological chemistry, Vol.287(43), pp.36105-36110
10/19/2012
DOI: 10.1074/jbc.M112.408450
PMCID: PMC3476278
PMID: 22948143
Abstract
Background:
Electrophysiological studies indicated that Cl
−
channel function of cystic fibrosis transmembrane conductance regulator (CFTR) can be coupled to adenylate kinase activity (ATP+AMP ⇆ 2 ADP).
Results:
CFTR catalyzes phosphoryl group transfer between a nucleotide triphosphate and a photoactivatable AMP analog.
Conclusion:
CFTR exhibits adenylate kinase activity.
Significance:
These data demonstrate biochemically that a membrane-bound ABC transporter can function as an adenylate kinase.
Cystic fibrosis transmembrane conductance regulator (CFTR) is a membrane-spanning adenosine 5′-triphosphate (ATP)-binding cassette (ABC) transporter. ABC transporters and other nuclear and cytoplasmic ABC proteins have ATPase activity that is coupled to their biological function. Recent studies with CFTR and two nonmembrane-bound ABC proteins, the DNA repair enzyme Rad50 and a structural maintenance of chromosome (SMC) protein, challenge the model that the function of all ABC proteins depends solely on their associated ATPase activity. Patch clamp studies indicated that in the presence of physiologically relevant concentrations of adenosine 5′-monophosphate (AMP), CFTR Cl
−
channel function is coupled to adenylate kinase activity (ATP+AMP ⇆ 2 ADP). Work with Rad50 and SMC showed that these enzymes catalyze both ATPase and adenylate kinase reactions. However, despite the supportive electrophysiological results with CFTR, there are no biochemical data demonstrating intrinsic adenylate kinase activity of a membrane-bound ABC transporter. We developed a biochemical assay for adenylate kinase activity, in which the radioactive γ-phosphate of a nucleotide triphosphate could transfer to a photoactivatable AMP analog. UV irradiation could then trap the
32
P on the adenylate kinase. With this assay, we discovered phosphoryl group transfer that labeled CFTR, thereby demonstrating its adenylate kinase activity. Our results also suggested that the interaction of nucleotide triphosphate with CFTR at ATP-binding site 2 is required for adenylate kinase activity. These biochemical data complement earlier biophysical studies of CFTR and indicate that the ABC transporter CFTR can function as an adenylate kinase.
Details
- Title: Subtitle
- Demonstration of Phosphoryl Group Transfer Indicates That the ATP-binding Cassette (ABC) Transporter Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Exhibits Adenylate Kinase Activity
- Creators
- Christoph O Randak - From the Departments ofAmanda R Ver Heul - From the Departments ofMichael J Welsh - Internal Medicine, and
- Resource Type
- Journal article
- Publication Details
- The Journal of biological chemistry, Vol.287(43), pp.36105-36110
- DOI
- 10.1074/jbc.M112.408450
- PMID
- 22948143
- PMCID
- PMC3476278
- NLM abbreviation
- J Biol Chem
- ISSN
- 0021-9258
- eISSN
- 1083-351X
- Publisher
- American Society for Biochemistry and Molecular Biology; 9650 Rockville Pike, Bethesda, MD 20814, U.S.A
- Grant note
- K08HL097071; HL51670; HL091842; HL102288 / National Institutes of Health
- Alternative title
- CFTR Exhibits Adenylate Kinase Activity
- Language
- English
- Date published
- 10/19/2012
- Academic Unit
- Neurology; Molecular Physiology and Biophysics; Pulmonary, Critical Care, and Occupational Medicine; Pulmonary Medicine; Stead Family Department of Pediatrics; Neurosurgery; Internal Medicine
- Record Identifier
- 9984020641702771
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