Fig. 2.

Alternate pathways for triglyceride exchange from VLDL to LDL. (A) The most straightforward model illustrating how triglyceride would be exchanged from VLDL to LDL using the VLDL-CETP-LDL ternary complex depicted by the asterisk. (B) We propose that existing data are more compatible with the following schema: i) VLDL interacts with the more stable HDL-CETP binary complex forming a VLDL-CETP-HDL ternary complex, (directly observed and depicted by an asterisk on the first line of Fig. 2B). ii) The ternary complex permits triglyceride enrichment of HDL and relative CE enrichment of VLDL. iii) The triglyceride-enriched HDL-CETP binary complex (depicted by a double asterisk) dissociates from VLDL. iv) Acting as a shuttle, the binary complex locates and interacts with LDL. v) Another ternary complex lipid exchange, HDL-CETP-LDL (directly observed and depicted by an asterisk on the lower line of Fig. 2B), results in triglyceride-enriched LDL species. vi) The HDL-CETP binary complex dissociates from LDL. vii) The triglyceride-enriched LDL would have a fate described in the text.