Component of the cornified envelope of keratinocytes. May link the cornified envelope to desmosomes and intermediate filaments. May act as a localization signal in PKB/AKT-mediated signaling. Homodimer or a heterodimer with EVPL (PubMed:9412476). 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 (via C-terminal linker domain) with BFSP2 (By similarity). Interacts with VIM (By similarity). Binds to the PH domain of AKT1 (PubMed:12244133). Interacts with FCGR1A (PubMed:15229321). May interact with PPHLN1 (PubMed:12853457). Expressed in stratified squamous epithelia and in some other epithelia. Expressed in the epidermis, nuclei of dermal fibroblasts, cell periphery of flattened keratinocytes, and dermal and epithelial cells lining the excretory ducts of the sweat glands in neonatal foreskin. During differentiation of epidermal keratinocytes. Belongs to the plakin or cytolinker family.