Connects cell membrane constituents to the actin cytoskeleton. May promote orthogonal branching of actin filaments and links actin filaments to membrane glycoproteins. Anchors various transmembrane proteins to the actin cytoskeleton (By similarity). Homodimer. Interacts with FLNA, FLNC, INPPL1, ITGB1A, ITGB1D, ITGB3, ITGB6, MYOT, MYOZ1, PSEN1 and PSEN2 (By similarity). Interacts with MICALL2. Interacts with RFLNA and RFLNB (PubMed:21709252,PubMed:24436304). Interacts with ASB2 isoform 1; the interaction targets FLNB for proteasomal degradation (PubMed:26343497). Expressed in hippocampus, cortex, cerebellar Purkinje cells and granule cell layers. Expressed within the ventricular, periventricular and subventricular zones at 12.5 dpc; olfactory epithelium, radial glial fibers, cortical plate and lateral ventricles at 16 dpc; in a lesser degree in lung, renal cortices and alimentary tract. Comprised of a NH2-terminal actin-binding domain, 24 internally homologous repeats and two hinge regions. Repeat 24 and the second hinge domain are important for dimer formation. The first hinge region prevents binding to ITGA and ITGB subunits (By similarity). ISGylation prevents ability to interact with the upstream activators of the JNK cascade and inhibits IFNA-induced JNK signaling. Ubiquitination by a SCF-like complex containing ASB2 isoform 1 leads to proteasomal degradation which promotes muscle differentiation. Belongs to the filamin family.