Translocation of AeSCP-2 protein into nucleus of Aag-2 mosquito cells in response to cholesterol and possible role in gene expression

Aedes aegypti Sterol Carrier Protein -2 (AeSCP-2) belongs to SCP-2 family of proteins. AeSCP-2 is involved in cholesterol uptake in the midgut and silencing of AeSCP-2 gene affected the development of larvae, adult longevity and fertility. Subcellular localization studies using electron microscopy have shown that the AeSCP-2 is found in mostly cytosol, and at much lower levels in the nucleus and the mitochondria. To understand the role of AeSCP-2 in the nucleus, Aag-2 (Ae. aegypti cell line) were transfected with over-expression vectors of EGFP and AeSCP-2/EGFP fusion protein. After 24hr of transfection, cell culture media was changed to media containing different known concentration of cholesterol. The localization of the AeSCP-2/EGFP inside the nucleus was observed using confocal microscope. Pearson’s co-localization coefficient values indicated an increase in the translocation of AeSCP-2/EGFP into the nucleus with increase in the concentration of cholesterol in the media. Movement of AeSCP-2 into nucleus in response to cholesterol indicates that it may pay a role in regulating gene expression. However, the further studies are required to identify the mechanism and its role in gene expression.