BFSP2
BFSP2 is a gene that encodes the protein phakinin in humans.
More than 99% of the vertebrate ocular lens consists of terminally differentiated lens fiber cells. Two lens-specific intermediate filament proteins, the protein product of this gene and filensin, are expressed only after fiber cell differentiation has begun. Both proteins are found in a structurally unique cytoskeletal element that is referred to as the beaded filament. Mutations in this gene have been associated with juvenile-onset, progressive cataracts and Dowling-Meara epidermolysis bullosa simplex.
The two BFSP proteins are put into a "type VI" of intermediate filament classification. Unlike other IFs that form unbranched links, the two proteins form a network of filaments together with CRYAA.
