Characterization of lipophorin receptor (LpR) mediating the binding of high density lipophorin (HDLp) in the silkworm, Bombyx mori

G. Ravikumar1a, K. V. Vardhana1, and H. K. Basavaraja

Seri-biotech Research Laboratory, Central Silk Board, Carmelaram Post, Kodathi, Bangalore 560035, India

Abstract

In an earlier report, we described the gene encoding a lipophorin receptor (LpR) of the silkworm, Bombyx mori L. (Lepidoptera: Bombycidae), and recombinant expression of the protein. The present study was performed to characterize the corresponding native BmLpR and its binding characteristics. Polyclonal anti-LpR antibody prepared against the cloned receptor fragment from the cytoplasmic domain specifically detected the receptor. Through immunoblotting, ovary and brain membrane protein samples of BmLpR have shown an apparent molecular mass of 105 kDa and 120 kDa under nonreducing and reducing conditions, respectively. Ligand binding of LpR supported the immunoblot results. It bound to high density lipophorin (HDLp) and has shown requirement of Ca2+ in binding. Further, a dose-dependent inhibition by EDTA was observed in receptor ligand binding. The characteristics of the BmLpR protein confirm the properties of a ligand-receptor interaction similar to that of vertebrate low density lipoprotein receptor (LDLR).

Keywords: Immunoblotting; ligand binding

Abbreviations: LpR, lipophorin receptor; Lp, lipophorin; HDLp, high density lipophorin; LDLR, low density lipoprotein receptor; VLDLR, very low density lipoprotein receptor; LBD, ligand binding domain

Correspondence: a ravikumarpillai@gmail.com; 1these authors contributed equally

Editor: Kostas Iatrou was Editor of this paper.

Received: 14 October 2010 | Accepted: 5 September 2011 | Published: 8 November 2011

ISSN: 1536-2442 | Volume 11, Number 150

Ravikumar G, Vardhana KV, Basavaraja HK. 2011. Characterization of lipophorin receptor (LpR) mediating the binding of high density lipophorin (HDLp) in the silkworm, Bombyx mori. Journal of Insect Science 11:150 available online: insectscience.org/11.150


Figure 1

Figure 2