LRRC52 (leucine rich repeat containing 52) functions as an auxiliary subunit that modulates large-conductance, voltage- and calcium-activated potassium (BK) channels and sperm-specific potassium channels. LRRC52 produces a marked hyperpolarizing shift (~100 mV) in BK channel voltage dependence of activation in the absence of calcium, establishing it as a γ-type auxiliary protein distinct from traditional β-subunits 1. The protein shows tissue-specific expression, being primarily found in testis 1. In human sperm, LRRC52 assembles with SLO3 to form the sperm potassium channel (KSper), which is essential for sperm function and male fertility 2. Functional disruption of LRRC52 inhibits KSper currents, depolarizes sperm membrane potential, and impairs sperm motility and acrosome reaction 2. The protein's role extends beyond reproductive function, as LRRC52 methylation patterns have been associated with multi-site atherosclerosis in clinical studies 3. Additionally, the antisense transcript LRRC52-AS1 is overexpressed in papillary thyroid cancer and associated with poor prognosis and lymph node metastasis 4 5. These findings indicate LRRC52's diverse roles in ion channel regulation, reproductive biology, cardiovascular disease, and cancer progression.