Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.23.5 (cathepsin D)
 4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Apical and narrow cells of the initial segment and intermediate zone of the adult rat epididymis were glutaraldehyde fixed and Epon embedded for routine light (LM) and electron (EM) microscopic analysis and Bouin fixed and paraffin embedded for LM immunocytochemical analysis in order to examine their structural features, distribution, and functions. The goblet-shaped apical cells comprised 10.7 +/- 1.0% of the total epithelial population in the proximal initial segment but only 1.3 +/- 0.5% in the intermediate zone. In the EM, these cells presented numerous mitochondria, few C-shaped vesicles, and a pale round or oblong nucleus located in the upper half of their cytoplasm. The slender elongated narrow cells increased from 2.8 +/- 0.3% in the proximal initial segment to 6.3 +/- 0.4% in the intermediate zone. In an EM analysis, these cells presented numerous C-shaped vesicles and mitochondria and a small flattened nucleus located in the upper half of their cytoplasm. The structural features of both these cell types differed not only from each other but also from the neighboring principal and basal cells of each region. Of the various antibodies examined to lysosomal proteins, narrow and apical cells expressed high levels of cathepsin D, while beta-hexosaminidase A was expressed at high levels in narrow cells but only moderately in apical cells. Apical cells were intensely reactive for the Yf subunit of glutathione S-transferase (GST)-P, whereas no reaction was seen in narrow cells; the Yo subunit of GST was localized within both cell types but only in the proximal initial segment. Narrow cells exclusively expressed carbonic anhydrase II. Selective differences in the immunolocalization of these various proteins were also noted between these two cell types and principal and basal cells. The localization of cathepsin D and beta-hexosaminidase A within narrow and apical cells suggests these cells may be involved in the degradation of specific proteins within their lysosomes, whereas the presence of GSTs may aid in protecting spermatozoa from a changing environment of harmful electrophiles. Localization of carbonic anhydrase II exclusively within narrow cells suggests that these cells may modify the pH of the lumen resulting in the quiescence of sperm motility in the proximal end of the epididymis. Together, the data indicate that apical and narrow cells differ not only from each other but also from principal and basal cells in their structure and relative distribution. They also express different proteins within the distinct epididymal regions, indicating that they perform different functions.
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PMID:Apical and narrow cells are distinct cell types differing in their structure, distribution, and functions in the adult rat epididymis. 879 11

Vasopressin regulates water and solute transport in the renal collecting duct. In addition to short-term regulation of aquaporin-2 trafficking, vasopressin also has long-term effects to regulate the abundances of aquaporins-2 and -3 and beta- and gamma-subunits of the epithelial sodium channel in collecting duct principal cells. To investigate further the direct and indirect long-term regulatory actions of vasopressin in the inner medullary collecting duct (IMCD), we used a proteomic approach [difference gel electrophoresis (DIGE) coupled with MALDI-TOF identification of differentially expressed protein spots]. DDAVP or vehicle was infused subcutaneously in Brattleboro rats for 3 days, and IMCD cells were purified from the inner medullas for proteomic analysis. Forty-three proteins were found to be regulated in response to vasopressin infusion, including 18 that were increased in abundance, 22 that were decreased, and 3 that were shifted in the gel, presumably because of posttranslational modification. Immunocytochemistry confirmed collecting duct expression of several of the proteins that were identified. Immunoblot analysis of nine of the proteins confirmed the changes seen by the DIGE method. Of these nine proteins, six were increased in response to DDAVP infusion: nitric oxide synthase-2 (NOS2), GRP78, heat shock protein-70, annexin II, glutaminase, and cathepsin D. The remaining three were decreased in response to DDAVP: aldehyde reductase I, adenylyl cyclase VI, and carbonic anhydrase II. The findings point to a role for vasopressin in the coordinate regulation of several determinants of nitric oxide levels (NOS2, arginase II, NADPH oxidase) and of proteins potentially involved in vasopressin escape (adenylyl cyclase VI and G protein-coupled receptor kinase 4).
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PMID:Proteomic analysis of long-term vasopressin action in the inner medullary collecting duct of the Brattleboro rat. 1453 64