2k9u
Solution NMR structure of the Filamin-migfilin complexSolution NMR structure of the Filamin-migfilin complex
Structural highlights
DiseaseFLNC_HUMAN Defects in FLNC are the cause of myopathy myofibrillar type 5 (MFM5) [MIM:609524. A neuromuscular disorder, usually with an adult onset, characterized by focal myofibrillar destruction and pathological cytoplasmic protein aggregations, and clinical features of a limb-girdle myopathy.[1] Defects in FLNC are the cause of myopathy distal type 4 (MPD4) [MIM:614065. MPD4 is a slowly progressive muscular disorder characterized by distal muscle weakness and atrophy affecting the upper and lower limbs. Onset occurs around the third to fourth decades of life, and patients remain ambulatory even after long disease duration. Muscle biopsy shows non-specific changes with no evidence of rods, necrosis, or inflammation.[2] FunctionFLNC_HUMAN Muscle-specific filamin, which plays a central role in muscle cells, probably by functioning as a large actin-cross-linking protein. May be involved in reorganizing the actin cytoskeleton in response to signaling events, and may also display structural functions at the Z lines in muscle cells. Critical for normal myogenesis and for maintaining the structural integrity of the muscle fibers. Publication Abstract from PubMedThe linkage of heterodimeric (alpha/beta) integrin receptors with their extracellular matrix ligands and intracellular actin cytoskeleton is a fundamental step for controlling cell adhesion and migration. Binding of the actin-linking protein, talin, to integrin beta cytoplasmic tails (CTs) induces high affinity ligand binding (integrin activation), whereas binding of another actin-linking protein, filamin, to the integrin beta CTs negatively regulates this process by blocking the talin-integrin interaction. Here we show structurally that migfilin, a novel cytoskeletal adaptor highly enriched in the integrin adhesion sites, strongly interacts with the same region in filamin where integrin beta CTs bind. We further demonstrate that the migfilin interaction dissociates filamin from integrin and promotes the talin/integrin binding and integrin activation. Migfilin thus acts as a molecular switch to disconnect filamin from integrin for regulating integrin activation and dynamics of extracellular matrix-actin linkage. Migfilin, a molecular switch in regulation of integrin activation.,Ithychanda SS, Das M, Ma YQ, Ding K, Wang X, Gupta S, Wu C, Plow EF, Qin J J Biol Chem. 2009 Feb 13;284(7):4713-22. doi: 10.1074/jbc.M807719200. Epub 2008, Dec 13. PMID:19074766[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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