Lipid Transport: Biochemistry of Hemolymph Lipophorin

Lipid transfer particle mediates the delivery of diacylglycerol from lipophorin to fat body in larval Manduca sexta

“…In summary, Lp in M. sexta larvae serves as a reusable shuttle that moves lipids from one tissue to another without itself entering the cell (4,40,41). This indicates that lipid transfer from Lp to fat body (and to other tissues) basically occurs at the interface between the hemolymph and the plasma membranes.…”

Site of synthesis, tissue distribution, and lipophorin transport of hydrocarbons in Blattella germanica (L.) nymphs

“…This suggests that although the abdominal epicuticle of cockroaches may be directly supplied with HC, epicuticle in other body regions would have to be supplied with HC by some transport mechanism. Grooming does provide an opportunity for insects to redistribute cuticular waxes, but several studies implicate a hemolymph transport pathway (Chino, 1985;Soulages and Wells, 1994;Schal et al, 1998). HC contained in the hemolymph of many insect species, including locusts, beetles, bees, flies, and cockroaches, is qualitatively similar to the respective epicuticular HC Chino, 1982, 1984;Blomquist et al, 1987;Pho et al, 1996;see Schal et al, 1998 for other examples).…”

“…Lipophorin shuttles multiple lipids through the hemolymph (Chino, 1985;Soulages and Wells, 1994) and it also functions as a plasma coagulagen and hemostatic agent. Because its principal functions change during development, it is unlikely that the lipophorin titer will correspond with any one of its ligands.…”

Lipophorin of female Blattella germanica (L.): characterization and relation to hemolymph titers of juvenile hormone and hydrocarbons

“…It has an apparent molecular weight of 670 kDa and it is composed of two subunits, one large apolipoprotein (212 kDa) and a small apolipoprotein (80 kDa). Other studies on the structure of Lp from different species of insects have also indicated that HDLp is composed of two subunits, but the molecular weight of the large subunit generally ranges from 220 to 250 kDa (275 kDa in larval Drosophila melanogaster; Fernando-Warnakulasuriya and Wells, 1988) and the small subunit from 70 to 85 kDa (Chino, 1985;Kanost et al, 1990;Soulages and Wells, 1994). The Blattella HDLp has a pI of 7.0 and stains positively with the periodic acid-Schiff reagent for the presence of carbohydrates, confirming the glycolipoprotein nature of B. germanica HDLp, like other lipophorins.…”

“…It has been purified and characterized from the hemolymph of insect species in the Diptera (Sarcophaga bullata, Van Mellaert et al, 1985;Aedes aegypti, Van Heusden et al, 1997;Drosophila melanogaster, Fernando-Warnakulasuriya and Wells, 1988), Hymenoptera (Apis mellifera, de Kort and Koopmanschap, 1986), Coleoptera (Leptinotarsa decemlineata, de Kort and Koopmanschap, 1987), Lepidoptera (several species, see review: Soulages and Wells, 1994), Hemiptera (Triatoma, Ganzalez et al, 1991;Rhodnius, Coelho et al, 1997), Orthoptera (Locusta migratoria, Chino and Kitazawa, 1981), Isop-HDLp facilitates absorption of neutral and polar lipids from the gut, and it transports diacylglycerols from the fat body to muscle to fuel flight (Chino, 1985;Van der Horst et al, 1993;Blacklock and Ryan, 1994;Soulages and Wells, 1994). Lipophorin also delivers pheromones to the cuticle (Gu et al, 1995;Pho et al, 1996) and specialized pheromone glands (Schal et al, 1998a), hydrocarbons to the epicuticle, fat body, and ovaries (Chino et al, 1977;Chino, 1985;Katagiri and de Kort, 1991;Gu et al, 1995;Schal et al, 1998b), and retinoids to yet undetermined locations (Kutty et al, 1996). It has specific, high-affinity binding sites for juvenile hormone (JH) III in species in the Coleoptera, Isoptera, Diptera, Hymenoptera and Dictyoptera (Trowell, 1992; and, in this context, the primary functions of HDLp are thought to be facilitation of transport of the hydrophobic hormone from the site of synthesis to target tissues (Whitmore and Gilbert, 1972) and protection of the hormone from enzymatic degradation by hemolymph esterases and epoxide hydrolases (Sanburg et al, 1975a, b;Hammock et al, 1975;Goodman, 1990;Lanzrein et al, 1993;Touhara et al, 1996).…”