A New N-Terminal Recognition Domain in Caveolin-1 Interacts with Sterol Carrier Protein-2 (SCP-2)

Parr, Rebecca D.; Martin, Gregory G.; Hostetler, Heather A.; Schroeder, Megan E.; Mir, Kiran D.; Kier, Ann B.; Ball, Joseph A.; Schroeder, Friedhelm

doi:10.1021/bi7002636

Cited by 22 publications

(24 citation statements)

References 97 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Effect of SUV lipid composition on the α-helical content of proSCP-2 and SCP-2 N-terminal peptides upon membrane interaction. Circular dichroism spectra were obtained as described in Experimental Procedures: (A and B) peptide [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Pro, (C and D) peptide Pro, (E and F) peptide Colocalization of Cy5-SCP-2 and Cy5-proSCP-2 with a plasma membrane marker in L cells. L cells were incubated in the presence of Cy5-SCP-2 (A-D) or Cy5-proSCP-2 (E-H) and the plasma membrane marker, AlexaFluor 488-cholera toxin B (AF488-CTB), and examined by laser scanning confocal microscopy (LSCM) as described in Experimental Procedures.…”

Section: Discussionmentioning

confidence: 99%

Structure and Function of the Sterol Carrier Protein-2 N-Terminal Presequence

et al. 2008

Self Cite

View full text Add to dashboard Cite

Although sterol carrier protein-2 (SCP-2) is encoded as a precursor protein (proSCP-2), little is known regarding the structure and function of the 20-amino acid N-terminal presequence. As shown herein, the presequence contains significant secondary structure and alters SCP-2: (i) secondary structure (CD), (ii) tertiary structure (aqueous exposure of Trp shown by UV absorbance, fluorescence, fluorescence quenching), (iii) ligand binding site [Trp response to ligands, peptide cross-linked by photoactivatable free cholesterol (FCBP)], (iv) selectivity for interaction with anionic phospholipid-rich membranes, (v) interaction with a peroxisomal import protein [FRET studies of Pex5p(C) binding], the N-terminal presequence increased SCP-2's affinity for Pex5p(C) by 10-fold, and (vi) intracellular targeting in living and fixed cells (confocal microscopy). Nearly 5-fold more SCP-2 than proSCP-2 colocalized with plasma membrane lipid rafts/caveolae (AF488-CTB), 2.8-fold more SCP-2 than proSCP-2 colocalized with a mitochondrial marker (Mitotracker), but nearly 2-fold less SCP-2 than proSCP-2 colocalized with peroxisomes (AF488-antibody to PMP70). These data indicate the importance of the N-terminal presequence in regulating SCP-2 structure, cholesterol localization within the ligand binding site, membrane association, and, potentially, intracellular targeting.Keywords sterol carrier protein-2; presequence; cholesterol; peroxin; peroxisome Sterol carrier protein-2 (SCP-2) 1 is a ubiquitous, soluble protein present at highest level in tissues involved in cholesterol uptake (intestine), oxidation (liver, steroidogenic cells), and/or elimination (liver) (reviewed in ref 1). SCP-2 exhibits high (nanomolar K d values) affinity for

show abstract

Section: Discussionmentioning

confidence: 99%

Structure and Function of the Sterol Carrier Protein-2 N-Terminal Presequence

et al. 2008

Self Cite

View full text Add to dashboard Cite

show abstract

“…1B) (39)(40)(41)44); (ii) SCP-2 directly interacting with caveolin-1 within the plasma membrane as observed from in vitro (coIP, CD) and in vivo (two hybrid, double immunofluorescence FRET, double immunogold EM) assays that revealed an average molecular interaction distance of ~48Å was measured (200). Specifically, SCP-2 has been shown to directly interact with the N-terminal sequence of amino acids of caveolin-1 (201). Finally, DHE transfer from lipid rafts/caveolae to serum lipoproteins was remarkably specific for the type of lipoprotein/apoprotein, while that to non-rafts was very slow and not specific (27).…”

Section: Plasma Membrane Sterol-rich Microdomains: In Vitro Studiesmentioning

confidence: 99%

Fluorescence Techniques Using Dehydroergosterol to Study Cholesterol Trafficking

McIntosh

Atshaves

Huang

et al. 2008

Lipids

Self Cite

View full text Add to dashboard Cite

Cholesterol itself has very few structural/chemical features suitable for real-time imaging in living cells. Thus, the advent of dehydroergosterol [ergosta-5,7,9(11),22-tetraen-3β-ol, DHE] the fluorescent sterol most structurally and functionally similar to cholesterol to date, has proven to be a major asset for real-time probing/elucidating the sterol environment and intracellular sterol trafficking in living organisms. DHE is a naturally-occurring, fluorescent sterol analog that faithfully mimics many of the properties of cholesterol. Because these properties are very sensitive to sterol structure and degradation, such studies require the use of extremely pure (>98%) quantities of fluorescent sterol. DHE is readily bound by cholesterol-binding proteins, is incorporated into lipoproteins (from the diet of animals or by exchange in vitro), and for real-time imaging studies is easily incorporated into cultured cells where it co-distributes with endogenous sterol. Incorporation from an ethanolic stock solution to cell culture media is effective, but this process forms an aqueous dispersion of dehydroergosterol crystals which can result in endocytic cellular uptake and distribution into lysosomes which is problematic in imaging DHE at the plasma membrane of living cells. In contrast, monomeric DHE can be incorporated from unilamellar vesicles by exchange/fusion with the plasma membrane or from DHE-methyl-β-cyclodextrin (DHE-MβCD) complexes by exchange with the plasma membrane. Both of the latter techniques can deliver large quantities of monomeric dehydroergosterol with significant distribution into the plasma membrane. The properties and behavior of DHE in protein-binding, lipoproteins, model membranes, biological membranes, lipid rafts/caveolae, and real-time imaging in living cells indicate that this naturally-occurring fluorescent sterol is a useful mimic for probing the properties of cholesterol in these systems. Keywordsdehydroergosterol; cholesterol; ergosterol; fluorescent sterols; microscopy Historical PerspectiveIn order to resolve the dynamics and factors governing cholesterol trafficking within cells, it is important to recognize that the cholesterol molecule has very few polar constituents (Fig. 1A). Consequently, cholesterol is poorly soluble in aqueous environments such as cytosol as evidenced by critical micellar concentrations of cholesterol and other sterols being very low, *To whom correspondence should be addressed: Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 862-1433, FAX: (979) NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript near 20-30 nM (1-5). The physiological impact of cholesterol's low aqueous solubility is that spontaneous cholesterol desorption from the cytofacial leaflet of the plasma membrane or lysosomal membrane into the cytosol for transfer to intracellular sites for esterification, oxidation, or secretion is extremely slow (t 1/2 3 hours-days) (6-9). Therefore, it is important to resolve factors...

show abstract

“…SCP-2 binds cholesterol with high affinity (K d near 4 nmol/L), binds plasma membrane caveolin-1, and enhances rapid (detectable in <1 min) directional cholesterol transfer from the plasma membrane to intracellular sites [74] . The human SCP2 is a basic protein that is believed to participate in the intracellular transport of cholesterol and various other lipids.…”

Section: Scp-2mentioning

confidence: 99%

A novel model of cholesterol efflux from lipid-loaded cells

et al. 2010

View full text Add to dashboard Cite

Cholesterol efflux from lipid-loaded cells is a key athero-protective event that counteracts cholesterol uptake. The imbalance between cholesterol efflux and uptake determines the prevention or development of atherosclerosis. Many proteins and factors participate in the cholesterol efflux event. However, there are currently no systematic models of reverse cholesterol transport (RCT) that include most RCT-related factors and events. On the basis of recent research findings from other and our laboratories, we propose a novel model of one center and four systems with coupling transportation and networking regulation. This model represents a common way of cholesterol efflux; however, the systems in the model consist of different proteins/factors in different cells. In this review, we evaluate the novel model in vascular smooth muscle cells (VSMCs) and macrophages, which are the most important original cells of foam cells. This novel model consists of 1) a caveolae transport center, 2) an intracellular trafficking system of the caveolin-1 complex, 3) a transmembrane transport system of the ABC-A1 complex, 4) a transmembrane transport system of the SR-B1 complex, and 5) an extracelluar trafficking system of HDL/Apo-A1. In brief, the caveolin-1 system transports cholesterol from intracellular compartments to caveolae. Subsequently, both ABC-A1 and SR-B1 complex systems transfer cholesterol from caveolae to extracellular HDL/Apo-A1. The four systems are linked by a regulatory network. This model provides a simple and concise way to understand the dynamic process of atherosclerosis.

show abstract

A New N-Terminal Recognition Domain in Caveolin-1 Interacts with Sterol Carrier Protein-2 (SCP-2)

Cited by 22 publications

References 97 publications

Structure and Function of the Sterol Carrier Protein-2 N-Terminal Presequence

Structure and Function of the Sterol Carrier Protein-2 N-Terminal Presequence

Fluorescence Techniques Using Dehydroergosterol to Study Cholesterol Trafficking

A novel model of cholesterol efflux from lipid-loaded cells

Contact Info

Product

Resources

About