tailieunhanh - Báo cáo Y học: Interaction of the anterior fat body protein with the hexamerin receptor in the blowfly Calliphora vicina

In late larvae of the blowfly, Calliphora vicina, arylphorin and LSP-2 proteins, which belong to the class of hexamerins, are selectively taken up by the fat body from the haemolymph. Hexamerin endocytosis is mediated by a specific membranebound receptor, the arylphorin-binding protein (ABP). Using the two-hybrid technique, we found that the anterior fat body protein (AFP) interacts with the hexamerin receptor. AFP, a homologue of the mammalian calcium-binding liver protein regucalcin (senescence marker protein-30), exhibits a strong binding affinity for a naturally occurring C-terminal cleavage fragment of the hexamerin receptor precursor (the P30 peptide) and other receptor cleavage products that contain. | Eur. J. Biochem. 269 954-960 2002 FEBS 2002 Interaction of the anterior fat body protein with the hexamerin receptor in the blowfly Calliphora vicina Immo A. Hansen Susanne R. Meyer Ingo Schafer and Klaus Scheller Department of Cell and Developmental Biology Biocenter of the University Wurzburg Germany In late larvae of the blowfly Calliphora vicina arylphorin and LSP-2 proteins which belong to the class of hexamerins are selectively taken up by the fat body from the haemolymph. Hexamerin endocytosis is mediated by a specific membranebound receptor the arylphorin-binding protein ABP . Using the two-hybrid technique we found that the anterior fat body protein AFP interacts with the hexamerin receptor. AFP a homologue of the mammalian calcium-binding liver protein regucalcin senescence marker protein-30 exhibits a strong binding affinity for a naturally occurring C-terminal cleavage fragment of the hexamerin receptor precursor the P30 peptide and other receptor cleavage products that contain P30. Expression of AFP mRNA and protein is restricted to the anterior part of the fat body tissue and to haemocytes in last-instar larvae. AFP mRNA occurs in all postembryonic developmental stages. Our results suggest that AFP plays a role in the regulation of hexamerin uptake by fat body cells along the anterior-posterior axis. Keywords anterior fat body protein Calliphora vicina cDNA sequence hexamerin receptor yeast two-hybrid system. The construction of adult tissues during the metamorphosis of holometablous insects requires large amounts of energy and building blocks. Before formation of the puparium fat body cells reabsorb proteins and other macromolecules that have accumulated in the haemolymph during the larval feeding period. The major fraction of incorporated proteins consists of arylphorins and LSP-2 which belong to the class of hexamerins haemocyanin-related proteins named according to their composition of six identical or closely related subunits 1 . Although some .