8dnh
Cryo-EM structure of nonmuscle beta-actin
Structural highlights
DiseaseACTB_HUMAN Defects in ACTB are a cause of dystonia juvenile-onset (DYTJ) [MIM:607371. DYTJ is a form of dystonia with juvenile onset. Dystonia is defined by the presence of sustained involuntary muscle contraction, often leading to abnormal postures. DYTJ patients manifest progressive, generalized, dopa-unresponsive dystonia, developmental malformations and sensory hearing loss.[1] Defects in ACTB are the cause of Baraitser-Winter syndrome type 1 (BRWS1) [MIM:243310. A rare developmental disorder characterized by the combination of congenital ptosis, high-arched eyebrows, hypertelorism, ocular colobomata, and a brain malformation consisting of anterior-predominant lissencephaly. Other typical features include postnatal short stature and microcephaly, intellectual disability, seizures, and hearing loss.[2] FunctionACTB_HUMAN Actins are highly conserved proteins that are involved in various types of cell motility and are ubiquitously expressed in all eukaryotic cells. Publication Abstract from PubMedActin isoforms organize into distinct networks that are essential for the normal function of eukaryotic cells. Despite a high level of sequence and structure conservation, subtle differences in their design principles determine the interaction with myosin motors and actin-binding proteins. Therefore, identifying how the structure of actin isoforms relates to function is important for our understanding of normal cytoskeletal physiology. Here, we report the high-resolution structures of filamentous skeletal muscle alpha-actin (3.37 A), cardiac muscle alpha-actin (3.07 A), ss-actin (2.99 A), and gamma-actin (3.38 A) in the Mg(2+).ADP state with their native post-translational modifications. The structures revealed isoform-specific conformations of the N-terminus that shift closer to the filament surface upon myosin binding, thereby establishing isoform-specific interfaces. Collectively, the structures of single-isotype, post-translationally modified bare skeletal muscle alpha-actin, cardiac muscle alpha-actin, ss-actin, and gamma-actin reveal general principles, similarities, and differences between isoforms. They complement the repertoire of known actin structures and allow for a comprehensive understanding of in vitro and in vivo functions of actin isoforms. Structural insights into actin isoforms.,Arora AS, Huang HL, Singh R, Narui Y, Suchenko A, Hatano T, Heissler SM, Balasubramanian MK, Chinthalapudi K Elife. 2023 Feb 15;12:e82015. doi: 10.7554/eLife.82015. PMID:36790143[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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