Characterization of the ATPase activity of human ATP-binding cassette transporter-2 (ABCA2)

Vladimir Beljanski; Athena Soulika; Jody M. Tucker; Danyelle M. Townsend; Warren Davis; Kenneth D. Tew

Characterization of the ATPase activity of human ATP-binding cassette transporter-2 (ABCA2)

Vladimir Beljanski, Athena Soulika, Jody M. Tucker, Danyelle M. Townsend, Warren Davis, Kenneth D. Tew

Research output: Contribution to journal › Article › peer-review

Abstract

Background: ABCA2 is a member of the ATP binding cassette transporter family with functional roles in cholesterol homeostasis and drug resistance. Materials and methods: In order to characterize its ATPase activity, we transfected HEK293 cells with an ABCA2 mammalian expression system and isolated ABCA2-enriched membranes. Results: We found no measurable ATPase activity of ABCA2 in isolated membranes, except in the presence of the methyl-β-cyclodextrin. However, competitive binding of a pseudo-substrate, 8-azido-[α-³²P]-ATP, was demonstrated. CHO cells transfected with ABCA2 did not have a higher rate of endogenous ATP hydrolysis when compared to the mock-transfected cells. Conclusion: Overall, we conclude that, while ABCA2 may have low levels of ATPase activity that can be substrate-stimulated, it is more likely to have a regulatory role in cell physiology.

Original language	English (US)
Pages (from-to)	657-660
Number of pages	4
Journal	In Vivo
Volume	19
Issue number	4
State	Published - Jul 2005
Externally published	Yes

Keywords

ABCA2 transporter
ATPase activity
Catalysis
Pseudo-substrate

ASJC Scopus subject areas

Medicine(all)

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title = "Characterization of the ATPase activity of human ATP-binding cassette transporter-2 (ABCA2)",

abstract = "Background: ABCA2 is a member of the ATP binding cassette transporter family with functional roles in cholesterol homeostasis and drug resistance. Materials and methods: In order to characterize its ATPase activity, we transfected HEK293 cells with an ABCA2 mammalian expression system and isolated ABCA2-enriched membranes. Results: We found no measurable ATPase activity of ABCA2 in isolated membranes, except in the presence of the methyl-β-cyclodextrin. However, competitive binding of a pseudo-substrate, 8-azido-[α-32P]-ATP, was demonstrated. CHO cells transfected with ABCA2 did not have a higher rate of endogenous ATP hydrolysis when compared to the mock-transfected cells. Conclusion: Overall, we conclude that, while ABCA2 may have low levels of ATPase activity that can be substrate-stimulated, it is more likely to have a regulatory role in cell physiology.",

keywords = "ABCA2 transporter, ATPase activity, Catalysis, Pseudo-substrate",

author = "Vladimir Beljanski and Athena Soulika and Tucker, {Jody M.} and Townsend, {Danyelle M.} and Warren Davis and Tew, {Kenneth D.}",

year = "2005",

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TY - JOUR

T1 - Characterization of the ATPase activity of human ATP-binding cassette transporter-2 (ABCA2)

AU - Beljanski, Vladimir

AU - Soulika, Athena

AU - Tucker, Jody M.

AU - Townsend, Danyelle M.

AU - Davis, Warren

AU - Tew, Kenneth D.

PY - 2005/7

Y1 - 2005/7

N2 - Background: ABCA2 is a member of the ATP binding cassette transporter family with functional roles in cholesterol homeostasis and drug resistance. Materials and methods: In order to characterize its ATPase activity, we transfected HEK293 cells with an ABCA2 mammalian expression system and isolated ABCA2-enriched membranes. Results: We found no measurable ATPase activity of ABCA2 in isolated membranes, except in the presence of the methyl-β-cyclodextrin. However, competitive binding of a pseudo-substrate, 8-azido-[α-32P]-ATP, was demonstrated. CHO cells transfected with ABCA2 did not have a higher rate of endogenous ATP hydrolysis when compared to the mock-transfected cells. Conclusion: Overall, we conclude that, while ABCA2 may have low levels of ATPase activity that can be substrate-stimulated, it is more likely to have a regulatory role in cell physiology.

AB - Background: ABCA2 is a member of the ATP binding cassette transporter family with functional roles in cholesterol homeostasis and drug resistance. Materials and methods: In order to characterize its ATPase activity, we transfected HEK293 cells with an ABCA2 mammalian expression system and isolated ABCA2-enriched membranes. Results: We found no measurable ATPase activity of ABCA2 in isolated membranes, except in the presence of the methyl-β-cyclodextrin. However, competitive binding of a pseudo-substrate, 8-azido-[α-32P]-ATP, was demonstrated. CHO cells transfected with ABCA2 did not have a higher rate of endogenous ATP hydrolysis when compared to the mock-transfected cells. Conclusion: Overall, we conclude that, while ABCA2 may have low levels of ATPase activity that can be substrate-stimulated, it is more likely to have a regulatory role in cell physiology.

KW - ABCA2 transporter

KW - ATPase activity

KW - Catalysis

KW - Pseudo-substrate

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