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Rat seminiferous epithelium contains a unique junction (Ectoplasmic specialization) with signaling properties both of cell/cell and cell/matrix junctions.
- Source :
-
Biology of reproduction [Biol Reprod] 2001 Jan; Vol. 64 (1), pp. 396-407. - Publication Year :
- 2001
-
Abstract
- The seminiferous epithelium contains unique actin related cell-cell junctions, termed ectoplasmic specializations (ESs). Turnover of these junctions is fundamental to sperm release and to movement of spermatocytes from basal to adluminal compartments of the epithelium during spermatogenesis. In this study we report several novel observations related to the spatial and temporal distribution of integrin-related signaling molecules at ESs. We confirm the presence of beta(1)-integrin at these sites and further demonstrate co-localization of integrin linked kinase (ILK). beta(1)-Integrin and ILK were shown by immunoprecipitation to associate in whole cell lysates of seminiferous epithelium. This observation provides the first evidence for a direct beta(1)-integrin/ILK interaction in noncultured epithelium. Pan-cadherin and beta-catenin antibodies did not react at ESs. Rather, antibodies reacted with desmosome-like junctions that are present both at basal junctional complexes between Sertoli cells and at sites of attachment to spermatogenic cells. Focal adhesion kinase (FAK), a known integrin-associated molecule, did not codistribute with beta(1)-integrins and did not associate with these adhesion molecules in immunoprecipitation studies. Although FAK was expressed in the epithelium, it appeared to be limited to the cytoplasm of early spermatogenic cells. Significantly, polyclonal antibodies against phosphotyrosine-containing residues reacted strongly at ESs, with highest levels detected during sperm release and turnover of basal junction complexes. Our observations indicate that ESs share cell signaling features both of cell-cell junctions and of cell-extracellular matrix junctions.
- Subjects :
- Actins analysis
Animals
Cadherins analysis
Cytoskeletal Proteins analysis
Cytoskeletal Proteins metabolism
Focal Adhesion Kinase 1
Focal Adhesion Protein-Tyrosine Kinases
Integrins analysis
Male
Microscopy, Immunoelectron
Paxillin
Phosphoproteins analysis
Phosphoproteins metabolism
Phosphotyrosine analysis
Protein Serine-Threonine Kinases analysis
Protein-Tyrosine Kinases analysis
Protein-Tyrosine Kinases metabolism
Rats
Rats, Sprague-Dawley
Sertoli Cells ultrastructure
Spermatogenesis
Spermatozoa physiology
Vinculin analysis
Vinculin metabolism
beta Catenin
Intercellular Junctions physiology
Seminiferous Epithelium ultrastructure
Signal Transduction
Trans-Activators
Subjects
Details
- Language :
- English
- ISSN :
- 0006-3363
- Volume :
- 64
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Biology of reproduction
- Publication Type :
- Academic Journal
- Accession number :
- 11133699
- Full Text :
- https://doi.org/10.1095/biolreprod64.1.396