Present in the thicker 16-17 nm junctions of mammalian lens fiber cells, where it may contribute to cell junctional organization. Acts as a receptor for calmodulin. May play an important role in both lens development and cataractogenesis. Seems to be associated with itself or another lens membrane component via disulfide bonds. Defects in Lim2 are the cause of the cataractous mouse mutant with total opacity of lens 3 (To3). Mice heterozygous or homozygous for the To3 mutation have total opacity of the lens with a dense cataract. In addition, the To3/To3 homozygotes exhibit microphthalmia, abnormally small eyes. Belongs to the PMP-22/EMP/MP20 family.