Membrane orientation of transmembrane segments 11 and 12 of MDR- and non-MDR-associated P-glycoproteins

Jian-Ting Zhang, Victor Ling

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

P-glycoprotein (Pgp) is a polytopic plasma membrane protein thought to function as a drug efflux pump. Two functional groups of Pgp have been identified in mammalian cells. One group (classes I and II) is associated with MDR and the other (class III) is not. Transmembrane (TM) sequences in Pgp have been postulated to be important for determining drug specificity. TM11 and TM12 have been predicted to bind drugs and play an important role in determining drug specificity of MDR-associated Pgps. Whether or not the membrane insertion and orientation of these TM segments differ amongst the different classes of Pgp has not been examined directly. In this study, we showed that membrane insertion and orientation of TM11 and TM12 of the MDR-associated Pgp may differ from the non-MDR-associated Pgp using an in vitro transcription and translation system. Charged amino acids surrounding TM domains are thought to be important in determining the topology of membrane proteins. The positively charged amino acids surrounding TM11 and TM12 of these two forms of Pgp are different. By site-directed mutagenesis we showed that these amino acids may affect the membrane orientation but not membrane insertion of these TMs. These results raise the possibility that a difference in membrane anchorage may be a underlying cause for the functional difference between the two groups of Pgp.

Original languageEnglish (US)
Pages (from-to)191-202
Number of pages12
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1153
Issue number2
DOIs
StatePublished - Dec 12 1993
Externally publishedYes

Fingerprint

P-Glycoproteins
P-Glycoprotein
Membranes
Amino Acids
Pharmaceutical Preparations
Membrane Proteins
Mutagenesis
Transcription
Cell membranes
Site-Directed Mutagenesis
Functional groups
Blood Proteins
Cells
Cell Membrane
Topology
Pumps

Keywords

  • Drug resistance
  • MDR
  • Membrane orientation
  • Multidrug resistance
  • Mutagenesis
  • P-glycoprotein
  • Topology

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Cell Biology

Cite this

Membrane orientation of transmembrane segments 11 and 12 of MDR- and non-MDR-associated P-glycoproteins. / Zhang, Jian-Ting; Ling, Victor.

In: Biochimica et Biophysica Acta - Biomembranes, Vol. 1153, No. 2, 12.12.1993, p. 191-202.

Research output: Contribution to journalArticle

@article{9fb2b00ba53f43169f7aa4d867e04e4f,
title = "Membrane orientation of transmembrane segments 11 and 12 of MDR- and non-MDR-associated P-glycoproteins",
abstract = "P-glycoprotein (Pgp) is a polytopic plasma membrane protein thought to function as a drug efflux pump. Two functional groups of Pgp have been identified in mammalian cells. One group (classes I and II) is associated with MDR and the other (class III) is not. Transmembrane (TM) sequences in Pgp have been postulated to be important for determining drug specificity. TM11 and TM12 have been predicted to bind drugs and play an important role in determining drug specificity of MDR-associated Pgps. Whether or not the membrane insertion and orientation of these TM segments differ amongst the different classes of Pgp has not been examined directly. In this study, we showed that membrane insertion and orientation of TM11 and TM12 of the MDR-associated Pgp may differ from the non-MDR-associated Pgp using an in vitro transcription and translation system. Charged amino acids surrounding TM domains are thought to be important in determining the topology of membrane proteins. The positively charged amino acids surrounding TM11 and TM12 of these two forms of Pgp are different. By site-directed mutagenesis we showed that these amino acids may affect the membrane orientation but not membrane insertion of these TMs. These results raise the possibility that a difference in membrane anchorage may be a underlying cause for the functional difference between the two groups of Pgp.",
keywords = "Drug resistance, MDR, Membrane orientation, Multidrug resistance, Mutagenesis, P-glycoprotein, Topology",
author = "Jian-Ting Zhang and Victor Ling",
year = "1993",
month = "12",
day = "12",
doi = "10.1016/0005-2736(93)90405-O",
language = "English (US)",
volume = "1153",
pages = "191--202",
journal = "Biochimica et Biophysica Acta - Biomembranes",
issn = "0005-2736",
publisher = "Elsevier",
number = "2",

}

TY - JOUR

T1 - Membrane orientation of transmembrane segments 11 and 12 of MDR- and non-MDR-associated P-glycoproteins

AU - Zhang, Jian-Ting

AU - Ling, Victor

PY - 1993/12/12

Y1 - 1993/12/12

N2 - P-glycoprotein (Pgp) is a polytopic plasma membrane protein thought to function as a drug efflux pump. Two functional groups of Pgp have been identified in mammalian cells. One group (classes I and II) is associated with MDR and the other (class III) is not. Transmembrane (TM) sequences in Pgp have been postulated to be important for determining drug specificity. TM11 and TM12 have been predicted to bind drugs and play an important role in determining drug specificity of MDR-associated Pgps. Whether or not the membrane insertion and orientation of these TM segments differ amongst the different classes of Pgp has not been examined directly. In this study, we showed that membrane insertion and orientation of TM11 and TM12 of the MDR-associated Pgp may differ from the non-MDR-associated Pgp using an in vitro transcription and translation system. Charged amino acids surrounding TM domains are thought to be important in determining the topology of membrane proteins. The positively charged amino acids surrounding TM11 and TM12 of these two forms of Pgp are different. By site-directed mutagenesis we showed that these amino acids may affect the membrane orientation but not membrane insertion of these TMs. These results raise the possibility that a difference in membrane anchorage may be a underlying cause for the functional difference between the two groups of Pgp.

AB - P-glycoprotein (Pgp) is a polytopic plasma membrane protein thought to function as a drug efflux pump. Two functional groups of Pgp have been identified in mammalian cells. One group (classes I and II) is associated with MDR and the other (class III) is not. Transmembrane (TM) sequences in Pgp have been postulated to be important for determining drug specificity. TM11 and TM12 have been predicted to bind drugs and play an important role in determining drug specificity of MDR-associated Pgps. Whether or not the membrane insertion and orientation of these TM segments differ amongst the different classes of Pgp has not been examined directly. In this study, we showed that membrane insertion and orientation of TM11 and TM12 of the MDR-associated Pgp may differ from the non-MDR-associated Pgp using an in vitro transcription and translation system. Charged amino acids surrounding TM domains are thought to be important in determining the topology of membrane proteins. The positively charged amino acids surrounding TM11 and TM12 of these two forms of Pgp are different. By site-directed mutagenesis we showed that these amino acids may affect the membrane orientation but not membrane insertion of these TMs. These results raise the possibility that a difference in membrane anchorage may be a underlying cause for the functional difference between the two groups of Pgp.

KW - Drug resistance

KW - MDR

KW - Membrane orientation

KW - Multidrug resistance

KW - Mutagenesis

KW - P-glycoprotein

KW - Topology

UR - http://www.scopus.com/inward/record.url?scp=0027742572&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0027742572&partnerID=8YFLogxK

U2 - 10.1016/0005-2736(93)90405-O

DO - 10.1016/0005-2736(93)90405-O

M3 - Article

C2 - 7903865

AN - SCOPUS:0027742572

VL - 1153

SP - 191

EP - 202

JO - Biochimica et Biophysica Acta - Biomembranes

JF - Biochimica et Biophysica Acta - Biomembranes

SN - 0005-2736

IS - 2

ER -