title: Interactions of caveolin-1 scaffolding and intramembrane regions containing a CRAC motif with cholesterol in lipid bilayers.
abstract: Caveolin-1 is a major structural protein of caveolae and specifically binds cholesterol (Chol). The caveolin scaffolding domain is thought to be involved in caveolin-Chol interaction through the sequence V94-T-K-Y-W-F-Y-R101, a motif that matches a cholesterol recognition amino-acid consensus (CRAC). In the present work, three CRAC-containing peptides, corresponding to caveolin-1 94-101, 82-101 and 93-126, were tested to study the role of the CRAC motif in the caveolin-Chol interaction in 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers using differential scanning calorimetry (DSC), fluorescence and circular dichroism (CD). The Y97I substituents of the three peptides and one peptide segment corresponding to caveolin-1 101-126 that excludes the CRAC motif were also tested for comparison. Our results showed the potency of these CRAC-containing peptides in sequestering Chol into domains and the enhanced role of the intramembrane domain and scaffolding domain for the potency. Of the three CRAC-containing peptides, the peptide 93-126 was particularly effective in promoting Chol segregation, while the peptide 82-101 was less potent in promoting the formation of domains than the peptide 93-126, but was more potent than the peptide 94-101. The domain partition of DPPC/Chol bilayers was not observed in the presence of the peptide 101-126, in contrast to the case in the presence of the peptide 93-126 at the same concentrations of peptide and Chol. The potency of the CRAC motif in Chol segregation was lowered by the Y97I mutation. The difference in structure may be a factor that contributes to different effects of these peptides on the distribution of Chol in the lipid membrane.
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun, 130012, PR China.
authors.forename: Guanhua
authors.initials: G
authors.lastname: Yang
authors.affiliation: Key Laboratory for Molecular Enzymology & Engineering, The Ministry of Education, Jilin University, Changchun 130012, PR China.
authors.forename: Haoran
authors.initials: H
authors.lastname: Xu
authors.affiliation: Key Laboratory for Molecular Enzymology & Engineering, The Ministry of Education, Jilin University, Changchun 130012, PR China.
authors.forename: Zhengqiang
authors.initials: Z
authors.lastname: Li
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun, 130012, PR China. Electronic address: feili@jlu.edu.cn.
authors.forename: Fei
authors.initials: F
authors.lastname: Li
mesh_terms: D020816:Amino Acid Motifs; D019943:Amino Acid Substitution; D051242:Caveolin 1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002784:Cholesterol / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry* / Q000378:metabolism; D020125:Mutation, Missense; D010455:Peptides / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: C495540:CAV1 protein, human; D051242:Caveolin 1; D008051:Lipid Bilayers; D010455:Peptides; D002784:Cholesterol
keywords: CRAC motif; Caveolin–cholesterol interaction; Cholesterol distribution; DSC; Phospholipid