LRRC38 is an auxiliary γ-subunit of large-conductance, voltage- and calcium-activated potassium (BK) channels that modulates their gating properties 1. As a leucine-rich repeat-containing membrane protein, LRRC38 produces a marked hyperpolarizing shift (~20 mV) in the BK channel's voltage dependence of activation in the absence of calcium, distinguishing it from its paralogs LRRC26, LRRC52, and LRRC55 which produce larger shifts 1. The modulatory function of LRRC38 depends on its transmembrane segment and adjacent intracellular positively charged amino acid clusters rather than its extracellular leucine-rich repeat domain 2. LRRC38 shows tissue-specific expression predominantly in secretory glands 1 and is preferentially expressed in skeletal muscle relative to other tissues 3. In cardiac tissue, LRRC38 is upregulated in the left ventricle and associated with cardiac muscle contraction and cellular component movement 4. The gene's role in regulating BK channel function across different tissues suggests physiological importance in controlling electrical signaling, though its specific clinical significance in heart failure and other pathologies requires further investigation.