Proteininduced Formation of Membrane Domains

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Protein-induced Formation of Membrane Domains

• Richard M. Epand and Raquel F. Epand
• Biochemistry Department, McMaster University,
  Hamilton, ON

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LWYIK
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LWYIK, 3.3 ppm slice
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COMPARISON OF THE CONSERVED TRYPTOPHAN-RICH
MOTIF IN THE MEMBRANE-PROXIMAL REGION OF gp41
WITH HOMOLOGOUS REGIONS
OF OTHER RETROVIRUSES
The putative cholesterol binding sites are
underlined. HIV-1

92/BR025-9
WQNLWTWFGITNWLWYIK GB8/C4

WANLWNWFDITNWLWYIK NL4-3

WASLWNWFNITNWLWYIK MN

WASLWNWFDITNWLWYIK HXB2

WASLWNWFNITNWLWYIK 92/UG024-2

WASLWNWFDITNWLWYIK SIV SIVcpzant

WSSLWNWFDITQWLWYIK SIVcpz(Q88004)

LNSWDVFGNWFDLASWIK SIVcpz

LNSWDVFGNWFDLASWIR SIVmac251

LNSWDVFGNWFDLASWIK SIVagm

LNSWDVFGNWFDLASWIK SIVmac

LNSWDVFGNWFDLTSWIK SIVsm

LNSWDIFGNWFDLTSWIK SIVsm84

LNSWDIFGNWFDLASWIR HIV-2 HIV2CBL24

LNSWDVFGNWFDLASWIK HIV-2ST

LNSWDVFGNWFDLTSWIK HIV2CBL21

LNSWDVFGNWFDLTSWIR N. Vincent, C. Genin and E.
Malvoisin.
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LWYIK Analogs
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• Peptides
• N-acetyl-LWYIK-amide segment adjacent to the
  transmembrane helix of the HIV-1 fusion protein
  gp41
• 4F N-acetyl-DWFKAFYDKVAEKFKEAF-amide
  anti-atherogenic amphipathic helical peptide

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SOPCCholesterol (6040)
LWYIK
4F
b
a
a
a
a
Heat
a
Cool
acholesterol crystals
b4F unfolding
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4F
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Membrane Proteins with YIYF
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Proteins with SSD without YIYF

• 7-Dehydrocholesterol reductase (has YYIF)
• Niemann-Pick C1
• Patched
• Dispatched
• Patched-related

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Cholesterol Redoxygen of 3-OH group Greycarbons
5 and 6 od the B ring
ent-cholesterol
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Difference between cholesterol enantiomers
  Taken from Westover and Covey (2005)
  Taken from Westover and Covey (2005)
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DSC of sequential heating and cooling scans.
The LWYIK peptide causes stereospecific
membrane rearrangement
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DSC of Chain Melting Transition  
DSC of Chain Melting Transition
   
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NAP-22 SEQUENCE Acidic amino acids in
red and basic amino acids in blue
N-MYRISTOYL-GGKLSKKKKGYNVNDEKAKDKDKKAEGAGTEEEGTQKE
SEPQAAADATEVKESAEEKPKDAADGEAKAEEKEADKAAAKEEAPKAEPE
KSEGAAEEQPEPAPAPEQEAAAPGPAAGGEAGGEAPKAGEASAESTGAAD
GAPQEEGEAKKTEAPAAGPEAKSDAAPAASDKPSTEPAPSSKETPAASEA
PSSAAKAPAPAAPAAEPQAEAPVASSEQSVAVKE PI
(Theoretical) 4.50 Molecular mass
21,659 Number of amino acids 219
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DSC of sequential heating and cooling scans. Doma
in formation is stereospecific.
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• CONCLUSIONS
• Certain peptides and proteins can
  promote the formation of cholesterol-rich
  domains.
• This phenomenon does not require high
  melting, long chain lipids.
• Peptides with CRAC motifs, such as
  LWYIK, preferentially interact with
  cholesterol-rich domains.
• Peptides can stabilize these domains
  either by preferentially associating with the
  phospholipid (4F) or with cholesterol (LWYIK).
• The segment YIYF of the Sterol Sensing Domain
  occurs at the end of a transmembrane helix in
  several proteins that interact with cholesterol.
  This segment in isolation has potent
  cholesterol-recruiting activity.
• The sequestering of cholesterol into domains
  exhibits specificity for the chirality of
  cholesterol.

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Acknowledgements G.M. Anantharamaiah,
UAB C. M. Yip and J. Shaw, University of
Toronto B. Sayer, McMaster University S.
Rychnovsky and J. Belany, UC, Irvine A.
Thomas and R. Brasseur, Centre de Biophysique
Moleculaire
Numerique, Gembloux, Belgium