FKBP1B encodes a peptidyl-prolyl cis-trans isomerase that plays critical roles in calcium signaling regulation, particularly in cardiac and neuronal tissues. The protein functions as a regulatory component of ryanodine receptors (RyRs), where it inhibits calcium-induced calcium release from the sarcoplasmic and endoplasmic reticulum 1. In cardiac muscle, FKBP1B helps regulate calcium release channels and contributes to proper cardiac muscle contraction by preventing pathological diastolic calcium leak from the sarcoplasmic reticulum 2. In the brain, declining FKBP1B expression appears linked to aging-related calcium dysregulation in hippocampal neurons, where reduced FKBP1B function leads to increased calcium responses and enlarged slow afterhyperpolarizations 1. The protein demonstrates neuroprotective properties, with increased FKBP1B expression associated with protection from Alzheimer's disease pathology 3. Additionally, FKBP1B exhibits antiviral functions, with homologs mediating resistance to dengue virus infection 4. Clinical relevance includes associations with autoimmune thyroid diseases 5 and potential therapeutic applications in neurodegenerative diseases, where peptide-driven upregulation of FKBP1B may restore neuronal calcium homeostasis 6.