ADP-ribosylation factor (ARF)-like 7 (ARL7) is induced by cholesterol loading and participates in apolipoprotein AI-dependent cholesterol export

Here, we identify ADP-ribosylation factor (ARF)-like 7 (ARL7) as the only ARF- and ARL-family member whose mRNA-expression is induced by liver X-receptor/retinoid X-receptor agonists or Cholesterol loading in human macrophages. Moreover, subcellular distribution of mutant and wild type ARL7-enhanced green Fluorescent protein (EGFP) supports that ARL7 may be involved in a vesicular transport step between a perinuclear compartment and the plasma membrane. Therefore, we investigated the effect of ARL7 over-expression on the Cholesterol secretory pathway. We found that expression of wild type and dominant active ARL7-EGFP stimulated the rate of apolipoprotein AI-specific Cholesterol efflux 1.7- and 2.8-fold. In contrast, expression of the dominant negative form of ARL7-EGFP led to approximately 50% inhibition of Cholesterol efflux. This data is consistent with a model in which ARL7 is involved in transport between a perinuclear compartment and the plasma membrane apparently linked to the ABCA1-mediated Cholesterol secretion pathway.