Interplay between calcium and endoplasmic reticulum stress

•ER/SR luminal proteins are involved in cellular Ca2+ signaling and modulation of stress sensors responsible for UPR stress coping signaling.•ER stress sensors are in a proximity to Ca2+ handling proteins where they influence Ca2+ transport and Ca2+ distribution between different cellular organelles.•ER stress sensors are found in membrane contact sites where they regulate communication and movement of molecules between organelles within the cellular reticular network.