Spontaneous aggregation of locust lipophorin during hemolymph collection

Chino, Haruo; Hirayama, Yuji; Kiyomoto, Yukari; Downer, Roger; Takahashi, K.

doi:10.1016/0020-1790(87)90148-x

Cited by 52 publications

(18 citation statements)

References 22 publications

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“…This confirms the finding by Shapiro et al [15] that centrifuging in a KBr gradient results in a one-step purification of insect lipophorins. The behavior of Colorado potato beetle lipophorin in PAG or agarose gel electrophoresis did not change with another method (flush method, [14]) of hemolymph collection.…”

Section: Resultsmentioning

confidence: 93%

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Molecular characteristics of lipophorin, the juvenile hormone‐binding protein in the hemolymph of the Colorado potato beetle

Kort

Koopmanschap

1987

Arch Insect Biochem Physiol

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Lipophorin, the protein that specifically binds juvenile hormone in the hemolymph of the Colorado potato beetle, Leptinotarsa decemlineata, is a high‐density lipoprotein of Mr ∼ 574,000. Lipophorin contains 43% lipid and is composed of two apoproteins: apolipophorin I (Mr ∼ 251,000) and apolipophorin II (Mr ∼ 78,000). Both apoproteins contain mannose residues. Carotenoids make up a substantial part of the lipid fraction. Lipophorin constitutes about 25% of the total hemolymph proteins. Its concentration in the hemolymph (26 μM in 4‐day‐old long‐day and 40 μM in 4‐day‐old short‐day beetles) changes with different physiological conditions concomitant with changes in total protein content. Lipophorin specifically binds 10R‐juvenile hormone III with high affinity. The dissociation constant for 10R‐juvenile hormone III is 12 ± 2 nM. One lipophorin molecule contains one specific juvenile hormone‐binding site. The concentration of binding sites therefore equals that of lipophorin in hemolymph.

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Section: Resultsmentioning

confidence: 93%

“…Hemocytes were sedimented by centrifuging at 10, OOOg for 4 min at 4°C. In a few experiments with Colorado potato beetles, hemolymph was collected by "flushing," which is essentially the method of Chino et al [14].…”

Section: Materials and Methods Insectsmentioning

confidence: 99%

Molecular characteristics of lipophorin, the juvenile hormone‐binding protein in the hemolymph of the Colorado potato beetle

Kort

Koopmanschap

1987

Arch Insect Biochem Physiol

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“…In addition, apoLp-II/I cleavage might enable a function for lipophorin in coagulation. Lipophorin has been implicated in this process by its abundant presence in clots (39)(40)(41)(42), capacity to aggregate (43,44), and interactions with other insect hemostasis factors (45). Moreover, the disappearance of apoLp-I but not apoLp-II from plasma during coagulation (46) suggests that apoLp-II/I cleavage enables distinct roles for apoLp-I and apoLp-II in coagulation.…”

Section: Discussionmentioning

confidence: 99%

Biosynthesis and secretion of insect lipoprotein: involvement of furin in cleavage of the apoB homolog, apolipophorin-II/I

Smolenaars

Kasperaitis

Richardson

et al. 2005

Journal of Lipid Research

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Lipoproteins mediate most of the lipid transport in the circulation of animals. In mammals, a single protein component, the nonexchangeable apolipoprotein B (apoB), provides the structural basis for the biosynthesis of neutral fattransporting lipoproteins (1, 2). Interestingly, the major lipoprotein of insects, lipophorin, contains two structural apolipoproteins, because the insect apoB homolog (3, 4), the precursor apolipophorin-II/I (apoLp-II/I), is cleaved during lipoprotein biosynthesis by the fat body (5, 6).Cleavage of apoLp-II/I can be related to the activity of furin, a member of the proprotein convertase (PC) family of subtilisin-like serine endoproteases that is mainly active in the trans -Golgi network (7). The preferred consensus substrate sequence for furin, R-X-K/R-R, is present in all apoLp-II/I sequences characterized to date (8-11). In agreement with the activity of furin, Locusta migratoria apoLp-II/I appears to be cleaved immediately C terminal of its furin substrate sequence, RQKR 720 , as indicated by the N-terminal sequence of apoLp-I (10).The predicted furin cleavage site in each insect apoLp-II/I is located in the large lipid transfer (LLT) domain, which constitutes the N-terminal region of apoLp-II/I that has sequence homology to that of apoB, the microsomal triglyceride transfer protein (MTP) large subunit, and vitellogenin (3, 4). In apoB, this domain is essential for lipoprotein biosynthesis. The interaction between the LLT domain of apoB and that of the MTP large subunit enables the assembly of apoB-containing lipoproteins (1, 2). The homology between apoB and apoLp-II/I, as well as the presence of an MTP large subunit in insects (12), suggest that the LLT domain of apoLp-II/I enables lipoprotein Abbreviations: apoB, apolipoprotein B; apoLp, apolipophorin; decRVKRcmk, decanoyl-Arg-Val-Lys-Arg-chloromethyl ketone; HDLp, high density lipophorin; LDLp, low density lipophorin; LDLR, low density lipoprotein receptor; LLT, large lipid transfer; MTP, microsomal triglyceride transfer protein; PC, proprotein convertase.

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“…If a fraction of the HDLp molecules are inactive, then the uptake rate at the apparent concentration would be lower than expected. As an example of how this might occur, Lp shows a tendency to form higher molecular weight aggregates during isolation procedures [8,26]. This behavior might be calcium-dependent [R. Van Antwerpen unpublished observations].…”

Section: Uptake Ratementioning

confidence: 98%

Lipophorin as a yolk precursor in Hyalophora cecropia: Uptake kinetics and competition with vitellogenin

Kulakosky

Telfer

1990

Arch Insect Biochem Physiol

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Vitellogenic follicles of Hyalophora cecropia were incubated in metabolically radiolabeled, high-density lipophorin isolated from pharate adult hemolymph by KBr density gradient centrifugation. The follicles transferred this probe from the incubation medium to the cortical yolk spheres in the oocyte by an energy-dependent and saturable mechanism. Vitellogenin and high-density lipophorin competed with each other for uptake, and are therefore concentrated by the follicle with a common mechanism. Microvitellin and lipophorin, in contrast, did not compete for uptake. The K(uptake) for the accumulation of high-density lipophorin was substantially higher than the value estimated earlier for vitellogenin (133 microM vs. 18 microM). This relationship helps explain why the shared concentrating mechanism does not deplete the lipid transport capacity of the hemolymph, and how a low vitellogenin: lipophorin molar ratio in the hemolymph yields a high ratio in the mature egg.

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Spontaneous aggregation of locust lipophorin during hemolymph collection

Cited by 52 publications

References 22 publications

Molecular characteristics of lipophorin, the juvenile hormone‐binding protein in the hemolymph of the Colorado potato beetle

Molecular characteristics of lipophorin, the juvenile hormone‐binding protein in the hemolymph of the Colorado potato beetle

Biosynthesis and secretion of insect lipoprotein: involvement of furin in cleavage of the apoB homolog, apolipophorin-II/I

Lipophorin as a yolk precursor in Hyalophora cecropia: Uptake kinetics and competition with vitellogenin

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