MAM mitochondria briefs

HDL cholesterol arriving at the ER through SR-B1 is the cue that assembles mitochondria-associated membranes

Plasma-membrane cholesterol delivered by high-density lipoproteins (HDL) through scavenger receptor class B type 1 (SR-B1) is rapidly moved to the endoplasmic reticulum (ER), where that sterol pool drives assembly of mitochondria-associated ER membranes (MAMs). Once formed, those contacts promote ER-mitochondria communication, esterify surplus cholesterol, and suppress cholesterol biosynthesis. The finding puts MAM assembly under extracellular lipoprotein supply rather than treating contacts as a static architecture.