Question

Explain the mechanism of SOCE and the contribution of Stim1 and Orai to vascular remodeling.

Answer 1

MECHANISM OF SOCE

Store - operated calcium entry is the process by which the emptying of endoplasmic reticulum calcium stores causes influx of calcium across the plsma membrane. This signaling pathway is widespread in eukaryotic cells and is involved in a host of cellular functions ranging from gene expression to regulation of proliferation.

STIMI - 1 - Orai 1 are the key proteins in SOCE. Orai1 is a plasma protein with four predicted transmembrane domains, represents the essential pore - forming subunits of SOCE channels. The information about the calcium concentration in the calcium stores ( endoplasmic reticulum ) is transmitted to Orai 1 via STIMI 1 which is located in the ER membrane. STMI 1 senses the calcium concentration in the stores.

SOCE appears to be a complex process that depends on temporal and spatial coordination of several distinct steps mediated by proteins in different cellular compartments. Orai 1 and Stimi 1 are central players in this process. They act as mediators for recruitment or activation of other Ca2+ channels. There are a number of mechanisms, including covalent modification, alternative splicing and alternative translation initiation.