Question

What is the relation between the mitochondrion and specifically the rough endoplasmic reticulum?why do they lie in close proximity when observed under a light microscope

Answer 1

The endoplasmic reticulum (ER) and  mitochondria are tubular organelles with a characteristic “network structure” that facilitates the formation of interorganellar connections.

The ER and mitochondria join together at multiple contact sites to form specific domains, termed mitochondria-ER associated membranes (MAMs), with distinct biochemical properties and a characteristic set of proteins.

The functions of these two organelles are coordinated and executed at the ER–mitochondria interface, which provides a platform for the regulation of different processes.

The roles played by the ER–mitochondria interface range from the coordination of calcium transfer to the regulation of mitochondrial fission and inflammasome formation as well as the provision of membranes for autophagy.

The novel and unconventional processes that occur at the ER–mitochondria interface demonstrate its multifunctional and intrinsically dynamic nature.

Highlights of their combined functions:

• Mitochondrial and ER crosstalk regulates mitochondrial homeostasis.

• The ER–mitochondria interface as platform for inflammasome formation

• The mitochondria associated membranes are crucial for autophagosome assembly and regulate autophagic machinery.

• MAMs as hotspot in signal transduction pathways.