Auxiliary protein of the large-conductance, voltage and calcium-activated potassium channel (BK alpha). Modulates gating properties by producing a marked shift in the BK channel's voltage dependence of activation in the hyperpolarizing direction, and in the absence of calcium (By similarity). KCNU1 channel auxiliary protein. May modulate KCNU1 gating properties, shifting KCNU1 gating to more negative potentials at a given pH. Interacts with KCNMA1 (By similarity). May interact with KCNU1; this interaction may be required for LRRC52 stability and may change the channel gating properties. Expression at the cell surface may require the presence of KCNU1. Testis-specific (at protein level). At the mRNA level, also detected in kidney, ventricle, spinal cord and skeletal muscle, although at lower levels compared to testis. Expression in testis at the protein level requires the presence of KCNU1. Very low expression levels in testis before postnatal day 25 (P25). Levels strongly increase between P25 and P30, and then remain high from P30 through P150. The transmembrane domain is necessary for interaction with KCNMA1. N-glycosylated.