More than 99% of the vertebrateocular lens is made up of terminally differentiated lens fiber cells. Two lens-specific intermediate filament proteins, phakinin (also known as CP49) and the protein product of this gene, filensin (or CP115), 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 (BF).[6]
The two BFSP proteins are put into a "type VI" of intermediate filament (IF) classification. Unlike other IFs that form unbranched links, the two proteins form a network of filaments together with CRYAA.[7][8]
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Rendtorff ND, Hansen C, Silahtaroglu A, Henriksen KF, Tommerup N (October 1998). "Isolation of the human beaded-filament structural protein 1 gene (BFSP1) and assignment to chromosome 20p11.23-p12.1". Genomics. 53 (1): 114–116. doi:10.1006/geno.1998.5478. PMID9787085.
Brunkener M, Georgatos SD (November 1992). "Membrane-binding properties of filensin, a cytoskeletal protein of the lens fiber cells". Journal of Cell Science. 103 ( Pt 3) (3): 709–718. doi:10.1242/jcs.103.3.709. PMID1478967.
Hess JF, Casselman JT, FitzGerald PG (January 1993). "cDNA analysis of the 49 kDa lens fiber cell cytoskeletal protein: a new, lens-specific member of the intermediate filament family?". Current Eye Research. 12 (1): 77–88. doi:10.3109/02713689308999499. PMID7679620.
Hess JF, Casselman JT, FitzGerald PG (January 1995). "Chromosomal locations of the genes for the beaded filament proteins CP 115 and CP 47". Current Eye Research. 14 (1): 11–18. doi:10.3109/02713689508999909. PMID7720401.
Carter JM, Hutcheson AM, Quinlan RA (February 1995). "In vitro studies on the assembly properties of the lens proteins CP49, CP115: coassembly with alpha-crystallin but not with vimentin". Experimental Eye Research. 60 (2): 181–192. doi:10.1016/S0014-4835(95)80009-3. PMID7781747.
Hess JF, Casselman JT, Kong AP, FitzGerald PG (May 1998). "Primary sequence, secondary structure, gene structure, and assembly properties suggests that the lens-specific cytoskeletal protein filensin represents a novel class of intermediate filament protein". Experimental Eye Research. 66 (5): 625–644. doi:10.1006/exer.1998.0478. PMID9628810.