TY - JOUR TI - Increasing evidence of mechanical force as a functional regulator in smooth muscle myosin light chain kinase AU - Baumann, Fabian AU - Bauer, Magnus Sebastian AU - Rees, Martin AU - Alexandrovich, Alexander AU - Gautel, Mathias AU - Pippig, Diana Angela AU - Gaub, Hermann Eduard A2 - Ha, Taekjip VL - 6 PY - 2017 DA - 2017/07/11 SP - e26473 C1 - eLife 2017;6:e26473 DO - 10.7554/eLife.26473 UR - https://doi.org/10.7554/eLife.26473 AB - Mechanosensitive proteins are key players in cytoskeletal remodeling, muscle contraction, cell migration and differentiation processes. Smooth muscle myosin light chain kinase (smMLCK) is a member of a diverse group of serine/threonine kinases that feature cytoskeletal association. Its catalytic activity is triggered by a conformational change upon Ca2+/calmodulin (Ca2+/CaM) binding. Due to its significant homology with the force-activated titin kinase, smMLCK is suspected to be also regulatable by mechanical stress. In this study, a CaM-independent activation mechanism for smMLCK by mechanical release of the inhibitory elements is investigated via high throughput AFM single-molecule force spectroscopy. The characteristic pattern of transitions between different smMLCK states and their variations in the presence of different substrates and ligands are presented. Interaction between kinase domain and regulatory light chain (RLC) substrate is identified in the absence of CaM, indicating restored substrate-binding capability due to mechanically induced removal of the auto-inhibitory regulatory region. KW - smooth muscle myosin light chain kinase KW - force-activation KW - cytoskeleton KW - auto-inhibition KW - single-molecule force spectroscopy KW - atomic force microscopy JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -