Myosin VI is a molecular motor that is thought to function both as a transporter and as a cytoskeletal anchor in vivo. Here we use optical tweezers to examine force generation by single molecules of myosin VI under physiological nucleotide concentrations. We find that myosin VI is an efficient transporter at loads of up to ∼2 pN but acts as a cytoskeletal anchor at higher loads. Our data and the resulting model are consistent with an indirect coupling of global structural motions to nucleotide binding and release. The model provides a mechanism by which load may regulate the dual functions of myosin VI in vivo. Our results suggest that myosin VI kinetics are tuned such that the motor maintains a consistent level of mechanical tension within the cell, a property potentially shared by other mechanosensitive proteins.
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http://dx.doi.org/10.1016/j.jmb.2010.10.010 | DOI Listing |
Pol J Vet Sci
December 2024
Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Dicle, 21280 Diyarbakır, Turkey.
Intermediate filaments (IFs) play a major role in determining and maintaining cell shape and anchoring intracellular organelles in place, in the tissues and organs of several species, starting from the early stages of development. This study was aimed at the immunohistochemical investigation of the presence, cellular localization and temporal distribution of the intermediate filaments keratin 8 (CK8), keratin 18 (CK18), keratin 19 (CK19), vimentin, desmin and laminin, all of which contribute to the formation of the cytoskeleton in the rat mammary gland during pregnancy, lactation and involution. On days 7, 14 and 21 of pregnancy (pregnancy period), on day 7 post-delivery (lactation period) and on day 7 post-weaning (involution period), under ketamine hydrochloride (Ketalar-Pfizer) (90 mg/kg) anesthesia, two mammary glands were fully excised from the abdominal region.
View Article and Find Full Text PDFJ Insect Physiol
December 2024
School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan 430079, China. Electronic address:
Wolbachia, as a widely infected intracellular symbiotic bacterium in Arthropoda, is able to manipulate the reproduction of insect hosts for facilitating their own transmission. Cytoplasmic incompatibility (CI) is the most common phenotype that Wolbachia induced in insect hosts where they resulted in the failure of uninfected egg hatch when fertilized with the sperm derived from Wolbachia-infected males, suggesting that the sperm are modified by Wolbachia during spermatogenesis. Although the molecular mechanisms of CI are beginning to be understood, the effects of Wolbachia on the symbiotic relationship and the proper dynamics of spermatogenesis have not yet been fully investigated.
View Article and Find Full Text PDFCytoskeleton (Hoboken)
December 2024
GN Ramachandran Protein Center, CSIR Institute of Microbial Technology, Chandigarh, India.
Z-ring formation by FtsZ, the master assembler of the divisome, is a key step in bacterial cell division. Membrane anchoring of the Z-ring requires the assistance of dedicated Z-ring binding proteins, such as SepF and FtsA. SepF participates in bundling and membrane anchoring of FtsZ in gram-positive bacteria.
View Article and Find Full Text PDFCell Commun Signal
December 2024
Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea.
The primary cilium is a cellular organelle whose assembly and disassembly are closely linked to the cell cycle. The centriole distal appendage (DA) is essential for the early stages of ciliogenesis by anchoring the mother centriole to the cell surface. Despite the identification of over twelve proteins constituting the DA, including CEP83, CEP89, CEP164, FBF1, and SCLT1, their specific functions in ciliary dynamics are not fully understood.
View Article and Find Full Text PDFNature
December 2024
Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA.
Duchenne muscular dystrophy (DMD) is a severe X-linked recessive disorder marked by progressive muscle wasting leading to premature mortality. Discovery of the DMD gene encoding dystrophin both revealed the cause of DMD and helped identify a family of at least ten dystrophin-associated proteins at the muscle cell membrane, collectively forming the dystrophin-glycoprotein complex (DGC). The DGC links the extracellular matrix to the cytoskeleton, but, despite its importance, its molecular architecture has remained elusive.
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