کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6450088 1415943 2016 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Full length articleMechanics of soft epithelial keratin networks depend on modular filament assembly kinetics
ترجمه فارسی عنوان
مقاله کامل مکانیک شبکه های کراتین اپیتلیال نرم بسته به سینتیک مونتاژ رشته های مدولار بستگی دارد
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی بیو مهندسی (مهندسی زیستی)
چکیده انگلیسی

Structural adaptability is a pivotal requirement of cytoskeletal structures, enabling their reorganization to meet the cellular needs. Shear stress, for instance, results in large morphological network changes of the human soft epithelial keratin pair K8:K18, and is accompanied by an increase in keratin phosphorylation levels. Yet the mechanisms responsible for the disruption of the network structure in vivo remain poorly understood. To understand the effect of the stress-related site-specific phosphorylation of the K8:K18 pair, we created phosphomimicry mutants - K8(S431E), K8(S73E), K18(S52E) - in vitro, and investigated the various steps of keratin assembly from monomer to network structure using fluorescence and electron microscopy, and using rheology characterized their network mechanical properties. We find that the addition of a charged group produces networks with depleted intra-connectivity, which translates to a mechanically weaker and more deformable network. This large variation in network structure is achieved by the formation of shorter mutant filaments, which exhibit differing assembly kinetics and a manifestly reduced capacity to form the extended structures characteristic of the wild-type system. The similarity in outcome for all the phosphomimicry mutants explored points to a more general mechanism of structural modulation of intermediate filaments via phosphorylation. Understanding the role of kinetic effects in the construction of these cytoskeletal biopolymer networks is critical to elucidating their structure-function properties, providing new insight for the design of keratin-inspired biomaterials.Statement of SignificanceStructural remodeling of cytoskeletal networks accompanies many cellular processes. Interestingly, levels of phosphorylation of the human soft epithelial keratin pair K8:K18 increase during their stress-related structural remodeling. Our multi-scale study sheds light on the poorly understood mechanism with which site-specific phosphorylation induces disruption of the keratin network structure in vivo. We show how phosphorylation reduces keratin filament length, an effect that propagates through to the mesoscopic structure, resulting in the formation of connectivity-depleted and mechanically weaker networks. We determine that the intrinsically-set filament-to-filament attractions that drive bundle assembly give rise to the structural variability by enabling the formation of kinetically-arrested structures. Overall, our results shed light on how self-assembled intermediate filament structures can be tailored to exhibit different structural functionalities.

392

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Acta Biomaterialia - Volume 43, 1 October 2016, Pages 218-229
نویسندگان
, , , , ,