Immunomolecular mapping of adherens junction and desmosomal components in normal human epidermis.
Adherens junctions (AJs) are cell-cell and cell-matrix junctions that are known to comprise the transmembrane and cytoplasmic components linked to the f-actin cytoskeleton. Although the presence of AJs han been confirmed in normal human epidermis, previous studies immunolocalizing AJ-related antigens have been controversial. The purpose of this study was to produce a more precise molecular mapping of AJs and their constituents in relation to desmosomes in normal human epidermal keratinocytes. Using an electron microscope (EM) method to optimally fix plasma membranes. AJ structures were typically seen as a narrowing of the intercellular space between two keratinocytes that was distinct from desmosomes and gap junctions. Such structures were consistently found more frequently in the upper epidermis than in the basal layer. Immunogold electron microscopy showed an absence of the AJ components (E-cadherin and beta-catenin) from desmosomal areas but they were present at interdesmosomal areas at sites of close membrane association. Conversely, the desmosomal components plakoglobin and plakophilin 1 were restricted only to the outer attachment plaque of the desmosome. These results further confirm that AJs have a distinct molecular composition and distribution from desmosomes and that they regularly occur between desmosomes along the keratinocyte plasma membrane to provide alternative cell-cell adhesion mechanisms.
Ishiko
A
A
Department of Dermatology, Keio University School of Medicine, Tokyo, Japan. ishiko@sc.itc.keio.ac.jp
Matsunaga
Y
Y
Masunaga
T
T
Aiso
S
S
Nishikawa
T
T
Shimizu
H
H
D000199:Actins / Q000737:chemistry / Q000378:metabolism; D022005:Adherens Junctions / Q000502:physiology*; D000941:Antigens / Q000737:chemistry; D015820:Cadherins / Q000378:metabolism; D002448:Cell Adhesion; D002462:Cell Membrane / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D003896:Desmosomes / Q000378:metabolism*; D004817:Epidermis / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D019084:Fluorescent Antibody Technique, Indirect; D005615:Freezing; D006801:Humans; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000378:metabolism; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D009993:Osmium Tetroxide / Q000494:pharmacology; D011485:Protein Binding; D012867:Skin / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism; D051176:beta Catenin
D000199:Actins; D000941:Antigens; C495270:CTNNB1 protein, human; D015820:Cadherins; D003598:Cytoskeletal Proteins; D015534:Trans-Activators; D051176:beta Catenin; D009993:Osmium Tetroxide