title: Rab11 is associated with epidermal lamellar granules.
abstract: Epidermal lamellar granules (LGs) are specialized organelles that transport and secrete various molecules, including lipids, proteases, protease inhibitors, and structural proteins, thereby providing a protective barrier against the environment. Abnormalities in LG-related molecules result in severe skin diseases, but their transport mechanisms are poorly understood. We studied the distribution of Rab11, a common GTPase in recycling endosomes, in normal human epidermis. Confocal laser scanning microscopy detected Rab11 immunoreactivity in differentiated epidermal keratinocytes. Staining was strong at the apical side of each cell, a pattern commonly seen in LG-associated molecules. Around the nuclei, Rab11 was colocalized with TGN46, a trans-Golgi network marker. Rab11 was also colocalized with known LG-molecules, namely lymphoepithelial Kazal-type-related inhibitor, corneodesmosine, cathepsin D, and glucosylceramides. Immunoelectron microscopy revealed that Rab11 was widely distributed along TGN and tubular-vesicular structures containing different LG molecules. The present results suggest that Rab11 plays a role in the intracellular trafficking of various types of LG-molecule from the TGN to the cell surface.
authors.affiliation: Department of Dermatology, Asahikawa Medical College, Asahikawa, Japan. akemi@asahikawa-med.ac.jp
authors.forename: Akemi
authors.initials: A
authors.lastname: Ishida-Yamamoto
authors.forename: Mari
authors.initials: M
authors.lastname: Kishibe
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Takahashi
authors.forename: Hajime
authors.initials: H
authors.lastname: Iizuka
mesh_terms: D002402:Cathepsin D / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D004817:Epidermis / Q000378:metabolism*; D005963:Glucosylceramides / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000737:chemistry; D018613:Microscopy, Confocal; D008954:Models, Biological; D015388:Organelles / Q000378:metabolism; D012867:Skin / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D021601:trans-Golgi Network / Q000378:metabolism; D000099193:rab11 GTP-Binding Proteins
chemical_list: D002402:Cathepsin D; D005963:Glucosylceramides; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D020691:rab GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins; C072237:TGOLN2 protein, human