Mechanobiology of organelles: illuminating their roles in mechanosensing and mechanotransduction

A growing body of evidence indicates that intracellular membrane-bound organelles can receive, modulate, and may even initiate mechanotransduction signaling.Organelles may sense mechanical forces in various ways such as through membrane deformation, changes in lipid packing, alterations in the membrane contact sites, through the cytoskeleton, or by altering the intraluminal fluid flow within organelles.The endoplasmic reticulum is equipped with mechanosensitive channels that can directly sense mechanical forces but was also shown to be the target of mechanotransduction signaling pathways that affect its functional organization.Mitochondrial fusion and fission were shown to be altered in response to extracellular and intracellular mechanical forces, thereby affecting the metabolic function of these organelles.The Golgi apparatus and the endosomes are involved in the mechanics of cell migration, as well as in mechanosensing and cellular mechanoprotection. Mechanobiology studies the mechanisms by which cells sense and respond to physical forces, and the role of these forces in shaping cells and tissues themselves. Mechanosensing can occur at the plasma membrane, which is directly exposed to external forces, but also in the cell’s interior, for example, through deformation of the nucleus. Less is known on how the function and morphology of organelles are influenced by alterations in their own mechanical properties, or by external forces. Here, we discuss recent advances on the mechanosensing and mechanotransduction of organelles, including the endoplasmic reticulum (ER), the Golgi apparatus, the endo-lysosmal system, and the mitochondria. We highlight open questions that need to be addressed to gain a broader understanding of the role of organelle mechanobiology.