Component of the sarcoglycan complex, a subcomplex of the dystrophin-glycoprotein complex which forms a link between the F-actin cytoskeleton and the extracellular matrix. In both neural tissues including cerebellar cortex, striatum, cerebral cortex, thalamus and hippocampus, and non-neural tissues including quadriceps muscle, liver, kidney, spleen, lung, testis and heart. Widely distributed in the brain, with a robust signal obtained from regions with dense neuronal packing such as the pyramidal cell layer of the hippocampus, cerebellar molecular layer, and cerebral cortex. Levels are highest in kidney, moderate in brain and lung, and low in skeletal muscle, liver, spleen and testis. Expressed at embryonic day 20, postnatal days 1, 7, 14, 36, six months and one and a half years. Highest level at E20. In muscle, expression is over 10 times higher at E20 and during the early postnatal period than in adults. In adults, expression levels are several-fold higher in brain, particularly in the cerebellar cortex, than in muscle. N-glycosylated. Ubiquitinated, leading to its degradation by the proteasome. Belongs to the sarcoglycan alpha/epsilon family.