title: Complementary roles of specific cysteines in keratin 14 toward the assembly, organization, and dynamics of intermediate filaments in skin keratinocytes.
abstract: We recently showed that inter-keratin disulfide bonding plays an important role in the assembly, organization, and dynamics of keratin intermediate filaments in skin keratinocytes. In particular, cysteine 367 located in the central α-helical rod domain of keratin 14 is necessary for the formation of a stable perinuclear network of keratin filaments (with type II partner keratin 5) in skin keratinocytes analyzed by static and live cell imaging. Here, we show that two additional cysteine residues located in the non-helical head domain of K14, Cys-4 and Cys-40, also participate in inter-keratin disulfide bonding and tandemly play a key role complementary to that of Cys-367 in the assembly, organization, and dynamics of keratin filaments in skin keratinocytes in primary culture. Analysis of K14 variants with single or multiple substitutions of cysteine residues points to a spatial and temporal hierarchy in how Cys-4/Cys-40 and Cys-367 regulate keratin assembly in vitro and filament dynamics in live keratinocytes in culture. Our findings substantiate the importance and complexity of a novel determinant, namely inter-keratin disulfide bonding, for the regulation of several aspects of keratin filaments in surface epithelia.
authors.affiliation: From the Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205 and.
authors.forename: Xia
authors.initials: X
authors.lastname: Feng
authors.affiliation: From the Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205 and the Departments of Biological Chemistry, Dermatology, and Oncology, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205 coulombe@jhu.edu.
authors.forename: Pierre A
authors.initials: PA
authors.lastname: Coulombe
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D003545:Cysteine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007382:Intermediate Filaments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D053547:Keratin-14 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D020125:Mutation, Missense; D017433:Protein Structure, Secondary; D012867:Skin / Q000166:cytology / Q000378:metabolism*
chemical_list: C507540:KRT14 protein, human; D053547:Keratin-14; C507446:Krt14 protein, mouse; D003545:Cysteine
keywords: cytoskeleton; disulfide bonding; epidermis; keratin; keratinocyte; nucleus