The exact roles of ABCA2 (Vulevic et al. 2001, Kaminski et al. 2001), ABCA6 (Kaminski & Wenzel et al. 2001), ABCA9 (Piehler et al. 2002) and ABCA10 (Wenzel et al. 2003), candidates for ABC lipid transporter-related activities, need to be elucidated. Even thought cholesterol-responsiveness has been noted in experimental systems, contribution of these proteins in regulation or in active transport is not yet clear.