Yeast two-hybrid screen reveals novel protein interactions of the cytoplasmic tail of lipophorin receptor in silkworm brain

Abstract

The silkworm, Bombyx mori lipophorin receptor (BmLpR), is expressed as splice variants. The alternative splicing of its primary gene transcripts yields four isoforms namely, LpR1 through 4. Among these isoforms, the LpR4 is unique, expressed only in the brain and CNS and with a unique amino acid tail sequence in its cytoplasmic domain. We carried out yeast two-hybrid screens to identify effector proteins that interact specifically with the cytoplasmic tail of LpR4 from a cDNA library derived from silkworm brain. The validity of the screen was confirmed by immunoblotting and further by co-immunoprecipitation. We have identified 11 novel proteins that are capable of interacting with the cytoplasmic domain of LpR4 in the silkworm brain. Most of these newly identified target proteins have known functions in lipid signalling, protein kinase pathways, cell motility, and organization of cytoskeleton, neurotransmission, and neuroprotection. These findings, for the first time, demonstrate a molecular link between LpR4 and the interacting proteins that might be involved in the regulation of signalling pathways in silkworm brain.

Keywords: LpR4; lipophorin receptor; signalling; silkworm; yeast two-hybrid assay.