Mitochondria-Associated Membrane Dysfunction in Neurodegeneration and Its Effects on Lipid Metabolism, Calcium Signaling, and Cell Fate

Abstract

Mitochondria-associated membranes (MAMs) are essential for cellular homeostasis. MAMs are specialized contact sites located between the endoplasmic reticulum (ER) and mitochondria and control apoptotic pathways, lipid metabolism, autophagy initiation, and calcium signaling, processes critical to the survival and function of neurons. Although this area of membrane biology remains understudied, increasing evidence links MAM dysfunction to the etiology of major neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis (ALS). MAMs consist of a network of protein complexes that mediate molecular exchange and ER-mitochondria tethering. MAMs regulate lipid flow in the brain, including phosphatidylserine and cholesterol; disruption of this process causes membrane instability and impaired synaptic function. Inositol 1,4,5-trisphosphate receptor-voltage-dependent anion channel 1 (IP3R-VDAC1) interactions at MAMs maintain calcium homeostasis, which is required for mitochondria to produce ATP; dysregulation promotes oxidative stress and neuronal death. An effective therapeutic approach for altering neurodegenerative processes is to restore the functional integrity of MAMs. Improving cell-to-cell interactions and modulating MAM-associated proteins may contribute to the restoration of calcium homeostasis and lipid metabolism, both of which are key for neuronal protection. MAMs significantly contribute to the progression of neurodegenerative diseases, making them promising targets for future therapeutic research. This review emphasizes the increasing importance of MAMs in the study of neurodegeneration and their potential as novel targets for membrane-based therapeutic interventions.