Related Experiment Video
Updated: Jun 9, 2025

Targeting Cysteine Thiols for in Vitro Site-specific Glycosylation of Recombinant Proteins
Published on: October 4, 2017
A Deep Dive into the N-Terminus of STIM Proteins: Structure-Function Analysis and Evolutionary Significance of the
Sasirekha Narayanasamy1, Hwei Ling Ong1, Indu S Ambudkar1
1Secretory Physiology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-1190, USA.
Abstract:
Calcium is an important second messenger that is involved in almost all cellular processes. Disruptions in the regulation of intracellular Ca2+ levels ([Ca2+]i) adversely impact normal physiological function and can contribute to various diseased conditions. STIM and Orai proteins play important roles in maintaining [Ca2+]i through store-operated Ca2+ entry (SOCE), with STIM being the primary regulatory protein that governs the function of Orai channels. STIM1 and STIM2 are single-pass ER-transmembrane proteins with their N- and C-termini located in the ER lumen and cytoplasm, respectively. The N-terminal EF-SAM domain of STIMs senses [Ca2+]ER changes, while the C-terminus mediates clustering in ER-PM junctions and gating of Orai1. ER-Ca2+ store depletion triggers activation of the STIM proteins, which involves their multimerization and clustering in ER-PM junctions, where they recruit and activate Orai1 channels. In this review, we will discuss the structure, organization, and function of EF-hand motifs and the SAM domain of STIM proteins in relation to those of other eukaryotic proteins.
Related Concept Videos
Structural Protein Function
Collagen, the most abundant protein in mammals, is found throughout the body. In connective tissue, such as skin, ligaments, and tendons, it provides tensile strength and elasticity. In bones and teeth, it mineralizes to...
Assembly of Signaling Complexes
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
Signal Sequences and Sorting Receptors
Conservation of Protein Domains Over Different Proteins
A limited set of protein domains often duplicate and recombine during evolution. These domains can be organized in different combinations to...
Amplifying Signals via Enzymatic Cascade
Generation of Straight or Branched Actin Filaments
Arp2/3 Complex
Arp2/3 complex is a seven-subunit complex consisting of two proteins similar to actin- Arp2 and Arp3, and five other subunits that help keep Arp2 and Arp3 inactive. When required, the complex is...

