MAMs

Mitochondria-associated membranes (MAMs) are specialized contact sites between the endoplasmic reticulum and mitochondria in eukaryotic cells. These interfaces are maintained by tethering protein complexes that bring the two organelles into close proximity, typically within a distance of about 10 to 30 nanometers. MAMs are dynamic and can change in response to the cell’s metabolic state and stress conditions.

Functions of MAMs include facilitating lipid exchange between the ER and mitochondria, contributing to the synthesis and distribution of phospholipids essential for membrane integrity and function. They also enable efficient calcium transfer from the ER to mitochondria, a process that regulates mitochondrial metabolism and ATP production. In addition, MAMs influence mitochondrial dynamics, including fission and fusion, and participate in signaling pathways related to autophagy and apoptosis, linking ER homeostasis to cell fate decisions.

Regulation and disease relevance: The extent and composition of MAM contacts are modulated by various tethering proteins and complexes, including mitofusin 2 and other ER–mitochondria tethering factors. Alterations in MAM structure or function have been associated with metabolic disorders, ageing, and neurodegenerative diseases. While some studies report consistent links between MAM dysfunction and conditions such as Alzheimer’s disease, obesity, and diabetes, findings can be context dependent and continue to be explored.

Other uses: The acronym MAMs is also used in other domains. In information technology, Mobile Application Management refers to systems and policies that secure and manage enterprise apps on mobile devices. The term MAMs thus requires domain context to avoid ambiguity.