Actin-binding proteins that crosslink F-actin calcium-independently to form the meshwork that is the actin cytoskeleton and also link this meshwork to the plasma membrane. Filamin A (filamin 1; ABP280, 2647 aa) is widely expressed and interacts with integrins, transmembrane receptor complexes, and second messengers. Mutation in the X-linked FLNA gene can cause the neurologic disorder periventricular heterotopia although there is some compensation by filamin B. Filamin B (filamin β; ABP 276/278, 2602 aa) has considerable similarity with filamin A (70% similarity at sequence level) but the gene is on chromosome 3 and the expression pattern is different. Four distinct skeletal disorders result from mutation in the FLNB gene, spondylocarpotarsal syndrome, autosomal dominant Larsen's syndrome, type I atelosteogenesis, and type III atelosteogenesis. Filamin C (filamin 2; ABP280A, 2725 aa) is very similar to both filamin 1 and filamin B and almost identical in the actin-binding region. Interacts with sarcoglycans and with the muscular dystrophy Ky protein.
Subjects: Medicine and Health.