The Ca²⁺ Sensor STIM in Human Diseases.

Area of Science:

• Cellular Biology
• Molecular Medicine
• Human Genetics

Background:

• The STIM (stromal interaction molecule) protein family regulates store-operated calcium entry (SOCE), maintaining intracellular calcium homeostasis.
• STIM1 and STIM2 proteins are key Ca2+ sensors in the endoplasmic reticulum, activating Orai/CRAC channels in the plasma membrane.
• Disrupted calcium signaling is implicated in numerous diseases, including neurodegenerative, cardiovascular, cancer, and immune disorders.

Purpose of the Study:

• To review rare conditions linked to STIM1 mutations.
• To summarize evidence on STIM2 gene alterations and associated developmental and congenital disorders.
• To underscore the importance of understanding STIM protein function in disease pathogenesis and therapeutic development.

Main Methods:

• Literature review of studies on STIM1 and STIM2 mutations and their clinical manifestations.
• Analysis of genetic alterations (duplications, deletions, mutations) in STIM1 and STIM2.
• Correlation of molecular mechanisms with observed phenotypes.

Main Results:

• STIM1 mutations can lead to gain- or loss-of-function, causing myopathy, hematological, and immunological disorders due to abnormal CRAC channel activation.
• STIM2 allele duplication or deletion is associated with a spectrum of developmental issues, including language and intellectual delay, microcephaly, and congenital anomalies.
• These findings highlight the critical role of STIM proteins in diverse physiological processes.

Conclusions:

• STIM1 and STIM2 proteins are vital for calcium signaling, and their dysregulation leads to distinct rare genetic disorders.
• Understanding STIM-related diseases is crucial for developing targeted therapies for a range of debilitating conditions.
• Further research into STIM protein function and dysfunction will advance diagnostics and treatments for these rare diseases.