Lipid Transport in Insects

Shapiro, Jeffrey P.; Law, John H.; Wells, Michael A.

doi:10.1146/annurev.en.33.010188.001501

Cited by 190 publications

(55 citation statements)

References 84 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The ability to bind retinoids may stem from the ability of RFABG to transport carotenoids assimilated from dietary sources to the visual system where it can be processed to visual pigments. In fact lipophorin is thought to transport carotenoids (2).…”

Section: Discussionmentioning

confidence: 99%

Molecular Characterization and Developmental Expression of a Retinoid- and Fatty Acid-binding Glycoprotein from Drosophila

Kutty¹,

Kutty²,

Kambadur³

et al. 1996

Journal of Biological Chemistry

View full text Add to dashboard Cite

A detailed understanding of the mechanism of lipid transport in insects has been hampered by the inability to identify the proapolipophorin gene that encodes apolipophorins I and II, the principal protein components of lipophorin, the lipid transport vehicle. Here we provide the first molecular description of the Drosophila gene encoding a retinoid-and fatty acid-binding glycoprotein (RFABG) and present evidence that it is a member of the proapolipophorin gene family. The gene, localized to the chromosome 4 (102 F region), encodes a 3351-amino acid protein that could serve as the precursor for the ϳ70-kDa and >200-kDa polypeptides associated with RFABG. The N-terminal sequence of the ϳ70-kDa polypeptide and that predicted for the >200-kDa polypeptide showed high sequence similarity to blowfly apolipophorin II and apolipophorin I, respectively. The RFABG precursor contains a signal peptide and exhibits a multidomain mosaic protein structure, which is typical of extracellular proteins. It has structural domains similar to lipid-binding proteins, namely vitellogenins and apolipoprotein B. The protein also contains a domain similar to the D domain of von Willebrand factor and mucin. The gene is expressed in the Drosophila embryo during development in cells that make up the amnioserosa and fat bodies. Immunolocalizations using specific antibodies against RFABG reveal that the protein is initially dispersed through the embryonic amnioserosa sac and latter concentrated at skeletal muscle-epidermis apodemeal contact junctions during larval development. This novel gene may play an important role in the transport of lipids, including retinoids and fatty acids, in insects.

show abstract

Section: Discussionmentioning

confidence: 99%

Molecular Characterization and Developmental Expression of a Retinoid- and Fatty Acid-binding Glycoprotein from Drosophila

Kutty¹,

Kutty²,

Kambadur³

et al. 1996

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…The lipophorin particle contains between 35% and 65% (weight %) lipid and two nonexchangeable apolipoprotein molecules-one apolipophorin I molecule of -250 kDa and one apolipophorin II molecule of "80 kDa (1)(2)(3)(4)(5). In those lipophorin particles containing >35% lipid, which is mainly due to an increase in the DG content, a third molecule, the exchangeable apolipoprotein apolipophorin III (apoLp-III; 18 kDa), is also found.…”

mentioning

confidence: 99%

“…The interaction of apoLp-III with lipid is of interest for several reasons. (i) apoLp-11I plays an essential role in the transport of large amounts of DG, which is the major source of energy for flight in many insects (1)(2)(3)(4)(5).…”

mentioning

confidence: 99%

Low concentrations of diacylglycerol promote the binding of apolipophorin III to a phospholipid bilayer: a surface plasmon resonance spectroscopy study.

Soulages

Salamon

Wells

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

The binding of the exchangeable apolipoprotein apolipophorin III (apoLp-III) to an egg phosphatidylcholine bilayer as a function of the concentration of diacylglycerol (DG) in the bilayer was studied by surface plasmon resonance spectroscopy. At a DG concentration of 2 mol % in the bilayer, the binding of apoLp-III reached saturation. Under saturating conditions, apoLp-III forms a closely packed monolayer -55 A thick, in which each molecule of protein occupies -500 A2 at the membrane surface. These dimensions are consistent with the molecular size of the apoLp-III molecule determined by x-ray crystallography, if apoLp-III binds to the bilayer with the long axis of the apoLp-III normal to the membrane surface. In the absence of protein, the overall structure of the lipid bilayer was not significantly changed up to 2.5 mol % DG. However, at 4 and 6 mol % DG, the presence of nonbilayer structures was observed. The addition of apoLp-III to a membrane containing 6 mol % DG promoted the formation of large lipid-protein complexes. These data support a two-step sequential binding mechanism for binding of apoLp-III to a lipid surface. The first step is a recognition process, consisting of the adsorption of apoLp-III to a nascent hydrophobic defect in the phospholipid bilayer caused by the presence of DG. This recognition process might depend on the presence of a hydrophobic sensor located at one of the ends of the long axis of the apoLp-III molecule but would be consolidated through Hbond and electrostatic interactions. Once primary binding is achieved, subsequent enlargement of the hydrophobic defect in the lipid surface would trigger the unfolding of the apolipoprotein and binding via the amphipathic a-helices. This two-step sequential binding mechanism could be a general mechanism for all exchangeable apolipoproteins. A possible physiological role of the ability of apoLp-III to bind to lipid structures in two orientations is also proposed.Lipophorin is the main lipoprotein found in the hemolymph of insects; it transports phospholipid, diacylglycerol (DG), and hydrocarbons among insect tissues. The lipophorin particle contains between 35% and 65% (weight %) lipid and two nonexchangeable apolipoprotein molecules-one apolipophorin I molecule of -250 kDa and one apolipophorin II molecule of "80 kDa (1-5). In those lipophorin particles containing >35% lipid, which is mainly due to an increase in the DG content, a third molecule, the exchangeable apolipoprotein apolipophorin III (apoLp-III; 18 kDa), is also found. The number of molecules of apoLp-III bound to the lipophorin is related to the DG content and varies between 0 and at least 16 molecules. The interaction of apoLp-III with lipid is of interest for several reasons. (i) apoLp-11I plays an essential role in the transport of large amounts of DG, which is the major source of energy for flight in many insects (1-5).(ii) apoLp-III is the only full-length exchangeable apolipopro-The publication costs of this article were defrayed in part by page charge payment....

show abstract

“…My faculty colleague Michael Wells was working on lipoproteins of neonatal rats, a project that had become boring to him and his students. Shapiro and Ryan dragged Wells into the field of insect proteins, and thus was born another great collaboration (26).…”

Section: Good Things Can Sometimes Happenmentioning

confidence: 99%

“…We could detect two different forms of lipoproteins, varying in density according to their lipid content. It was known from work by Goldsworthy, Beenakkers, Van Der Horst, and others that lipids were mobilized in locust hemolymph in preparation for flight (26). The process was initiated by the release of a small peptide, adipokinetic hormone (AKH), and involved the participation of a third small apoprotein.…”

Section: Fat and Flightmentioning

confidence: 99%

Breaking Good: A Chemist Wanders into Entomology

Law

2015

Annu. Rev. Entomol.

View full text Add to dashboard Cite

In this highly personal account of my career in science, I try to show how many others influenced its course. I was able to abandon work in pure chemistry and microbiology and to take up research in entomology only with the help of others. My faith in the value of collaborative, interdisciplinary work has been the key to success. Our focus on proteins of insect hemolymph has provided valuable insights into insect biochemistry and physiology.

show abstract

Lipid Transport in Insects

Cited by 190 publications

References 84 publications

Molecular Characterization and Developmental Expression of a Retinoid- and Fatty Acid-binding Glycoprotein from Drosophila

Molecular Characterization and Developmental Expression of a Retinoid- and Fatty Acid-binding Glycoprotein from Drosophila

Low concentrations of diacylglycerol promote the binding of apolipophorin III to a phospholipid bilayer: a surface plasmon resonance spectroscopy study.

Breaking Good: A Chemist Wanders into Entomology

Contact Info

Product

Resources

About