title: Restricted expression of cell adhesion kinase-beta in rat tissues.
abstract: Cell adhesion kinase-beta (CAK-beta) is a protein tyrosine kinase of the focal adhesion kinase subfamily, which contains large amino- and carboxyl-terminal domains. We studied the tissue distribution of CAK-beta and its mRNA by immunohistochemical staining and in situ hybridization. In rat brain, CAK-beta was mainly found in the medulla whereas CAK-beta mRNA was expressed in most neurons, especially pyramidal cells and Purkinje cells. In the small intestine, CAK-beta protein and mRNA were detected in the absorptive epithelial cells, and the protein was concentrated in the brush border. Double immunostaining for CAK-beta and actin showed that they co-localized in the brush border of small intestine cells. Immunoelectron micrography revealed that the anti-CAK-beta antibody localized within microvilli. In the kidney, the protein was mainly expressed in proximal tubular cells, which have well developed microvilli, although CAK-beta mRNA was observed in most urinary tubular cells. In other tissues, the ciliated cells of the epididymis strongly expressed CAK-beta mRNA and CAK-beta localized in the cilia. In addition, alpha- and beta-tubulin were identified in the rat brain lysates immunoprecipitated with anti-CAK-beta antibody. The present results demonstrate that CAK-beta is present at relatively high levels in cilia, axons, and microvilli. This suggests that CAK-beta may play important roles in the functions of these structures or that the CAK-beta-related signaling pathway is closely associated with cytoskeletal components.
authors.affiliation: Department of Pathology, Sapporo Medical University School of Medicine, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Mitaka
authors.forename: M
authors.initials: M
authors.lastname: Shindoh
authors.forename: Y
authors.initials: Y
authors.lastname: Mochizuki
authors.forename: H
authors.initials: H
authors.lastname: Sasaki
authors.forename: M
authors.initials: M
authors.lastname: Ishino
authors.forename: M
authors.initials: M
authors.lastname: Matsuya
authors.forename: T
authors.initials: T
authors.lastname: Ninomiya
authors.forename: T
authors.initials: T
authors.lastname: Sasaki
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology / Q000276:immunology; D002458:Cell Fractionation; D051418:Focal Adhesion Kinase 2; D007421:Intestine, Small / Q000201:enzymology / Q000648:ultrastructure; D016253:Microscopy, Immunoelectron; D009928:Organ Specificity / Q000276:immunology; D011233:Precipitin Tests; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000737:chemistry* / Q000276:immunology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014404:Tubulin / Q000737:chemistry / Q000276:immunology
chemical_list: D014404:Tubulin; D011505:Protein-Tyrosine Kinases; D051418:Focal Adhesion Kinase 2; C496054:Ptk2b protein, rat