Required for the correct formation of lens intermediate filaments as part of a complex composed of BFSP1, BFSP2 and CRYAA (PubMed:28935373). Plays a role in maintenance of retinal lens optical clarity (By similarity). Part of a complex required for lens intermediate filament formation composed of BFSP1, BFSP2 and CRYAA (PubMed:28935373). Found in a complex composed of PPL (via C-terminal linker domain), BFSP1 and BFSP2 in the retinal lens (By similarity). Within the complex interacts with PPL (via C-terminal linker domain) and with BFSP1 (By similarity). Identified in a complex that contains VIM, EZR, AHNAK, BFSP1, BFSP2, ANK2, PLEC, PRX and spectrin (By similarity). Interacts with LGSN (By similarity). Interacts with VIM (By similarity). Expressed primarily at the plasma membrane in peripheral lens fiber cells, however also localizes to the cytoplasm in mature lens fiber cells. Lens. The disease is caused by variants affecting the gene represented in this entry. Belongs to the intermediate filament family.