Localization Of Cathepsin Research Articles

Extra-and intracellular collagen resorption by smooth muscle cells in postpartum uterine involution

Localization of cathepsin B in rat uterus during postpartum involution is studied using electron histochemical technique. High extracellular activity of cathepsin B and accumulation of products on the cytolemma of smooth muscle cells and adjacent collagen fibrils are revealed. These findings suggest that smooth muscle cells participate in the extracellular collagen degradation via secretion of cathepsin B.

Immunohistochemical localization of lysosomal cathepsin D in schwannomas

The immunohistochemical localization of cathepsin D (CD) was demonstrated for the first time in 54 schwannomas (32 intra- and 22 extracranial; 47 benign and 7 malignant) and 5 normal nerve fibers. Granular or vesicular CD-reactive structures were observed in all normal Schwann cells. All tumors contained CD-reactive tumor cells, although the population of CD-reactive tumor cells, the density, intracellular localization, and morphology of CD-reactive structures, and the intensity of CD immunoreactivity varied from case to case, portion to portion, and cell to cell, differing variously from those in normal Schwann cells. The variations were greater in malignant than in benign schwannomas. In mildly degenerate tumor cells, CD immunoreactivity was increased, possibly in response to the increased intracellular degenerate proteins, suggesting that the mechanism of induction of lysosomal proteases preserved in normal cells is not affected by the process of neoplastic transformation. In lesions of severe degeneration or necrosis, CD immunoreactivity was lost in most tumor cells but was strong in macrophages invading the lesions and perivascular regions. CD immunoreactivity was observed at various intensities in tumor cells in the Antoni type A area but not in most tumor cells in the Antoni type B area, suggesting that Antoni type B lesions show degenerative changes. The presence of CD-reactive tumor cells in all tumors examined and strong CD immunoreactivity observed at the invasion front of tumors in some cases of benign or malignant schwannoma suggests the possible role of CD in tumor invasion in some cases.

Tomography of cells by confocal laser scanning microscopy and computer-assisted three-dimensional image reconstruction: localization of cathepsin B in tumor cells penetrating collagen gels in vitro.

We used the nondestructive procedures of confocal laser scanning microscopy in combination with computer-assisted methods to visualize tumor cells in the process of penetrating collagen gels. Three independent sets of images were collected. The image information of all data sets was combined into one image, giving a three-dimensional (3D) impression at high light microscopic resolution and sensitivity. We collected information about the extracellular matrix using the reflection mode, the cell surface/morphology by staining with the fluorescent dye DiOC6(3), and the distribution of cathepsin B by Cy-3-labeled immunolocalization. The specific aim of our study was visualization of the spatial relationship of cell organelles as far as they contain the enzyme cathepsin B to cell morphology and motility in a 3D model of extracellular matrix. The majority of the enzyme was localized pericellularly, with no visible relationship to the direction of movement. However, substantial amounts also appeared in intramatrix pseudopodia and associated with the extracellular face of the plasma membrane, which may be indicative either of secretion and/or epicellular activity. Our approach has general applicability to study of the spatial relationships of cell compartments and their possible reorganization over time. This could open new horizons in understanding cell structure and function.

Immunocytochemical study of cathepsin L and rat salivary cystatin-3 in rat osteoclasts treated with E-64 in vivo

The localization of cathepsin L and rat salivary cystatin-3 (RSC-3) in rat osteoclasts (rat femoral and alveolar bones) treated with or without E-64 (control) was examined immunocytochemically. In osteoclasts pretreated with E-64, immunoreactivity for cathepsin L was very weak extracellularly compared to that in the control osteoclasts. However, it was strong intracellularly. The localization of RSC-3 was unclear in the control osteoclasts, while in E-64 treated osteoclasts, both the clear zone and ruffled border areas showed a very strong immunoreaction. At the electron-microscopic level, in normal osteoclasts, numerous immunoreaction products for cathepsin L were found extracellularly in the bone matrix under the ruffled border, while few intracellular products were observed. In contrast, in the 1E-64-treated osteoclasts, only a few immunoreaction products were found extracellularly, while intracellularly cathepsin L was found in numerous endosome-lysosomel vacuoles. In the immunoreaction for RSC-3, the cytoplasm of the ruffled border was positive, and the tips of the RSC3-positive ruffled border appeared to enter deeply into the bone matrix. Intracellularly, the granular reaction products of RSC-3 were found in the vacuoles (probably autophagolysosomes). Thus, in E-64-treated osteoclasts, inhibition of the extracellular release of cathepsin L was demonstrated. In addition, intralysosomal accumulation of RSC-3 and deep penetration of the RSC-3-positive ruffled border into the bone matrix were found. These findings suggest that RSC-3 is associated with the inhibition of cathepsin L in both the lysosomes (in the osteoclasts) and bone matrix.

Ultrastructural localization of cathepsin B in gingival tissue from chronic periodontitis patients.

Loss of tooth support during chronic periodontitis is very likely to involve tissue proteases such as cathepsin B. The distribution of this enzyme was, therefore, examined in ultrathin sections of gingival tissue embedded in acrylic resin and labelled with a sheep polyclonal antibody and gold-conjugated secondary antibody. Macrophages and fibroblasts in both inflamed and non-inflamed areas of tissue showed labelling, and this was strongest in lysosomes, corresponding to the normal intracellular location of cathepsin B. However, additional gold particles were found on the surface of these cells. Monocytes in inflamed areas also had surface labelling, some of which was present on microvilli. Labelled collagen fibres adjacent to all three cell types indicated that cathepsin B had been released into the immediate extracellular environment. Plasma membrane cathepsin B has previously been associated with cancers, but enzyme redistribution and release in the gingiva may have been linked to the inflammatory response, since fibroblasts and macrophages in non-inflamed areas showed less labelling of their surface and adjacent collagen. The collagen labelling added to evidence that cathepsin B can function extracellularly as well as intracellularly in connective tissue degradation. This destructive role for the enzyme is supported by our earlier measurements of increased biochemical activity in chronic periodontitis.

The cysteine protease cathepsin B in cancer

Of the cysteine proteases, cathepsin B has been most often implicated in tumor progression. Accumulating evidence indicates that the regulation of cathepsin B and other cysteine proteases is under both transcriptional and posttranscriptional control. The elucidation of such control mechanisms may be important for therapeutic strategies aimed at reducing cathepsin B overexpression in tumors and other pathologies. Transcription initiation at more than one initiation site and/or the induction of alternative splicing of mRNA may lead to the production of transcripts that differ in their rate of translation or their stability. Hence, the amount of protein produced may not be proportional to the amount of mRNA observed in tissues. Transcripts lacking exon 3 would encode a truncated procathepsin B, a form predicted to be trafficked to the cytoplasm due to the absence of its signal peptide. Evidence of alterations in trafficking of cathepsin B and distribution of organelles labeling for cathepsin B to more peripheral, basolateral or cell membrane localizations is seen in bladder, breast, colon, prostate and thyroid carcinomas and in gliomas. These may reflect alterations in the cytoskeleton as similar changes in localization of cathepsin B accompany the rearrangement of cytoskeletal elements and the acquisition of an invasive phenotype in MCF-10A breast epithelial cell lines after transfection with oncogenic c-Ha-ras. Alterations in trafficking of cathepsin B and other cysteine proteases may thus be brought about by changes in signal transduction, induced by transfection with an activated oncogene. Signal-transduction pathways as well as the enzymes directly involved in the invasive degradation of basement membranes may therefore both be targets for therapeutic intervention. The results of recent studies suggest that cathepsins B and L are more stable in the extracellular environment than previously believed and so could play a significant extracellular role in invasive cancer.

Cytosolic proteolysis of tau by cathepsin D in hippocampus following suppression of cathepsins B and L.

Incubation of cultured hippocampal slices with an inhibitor [N-CBZ-L-phenylalanyl-L-alanine-diazomethyl ketone (ZPAD)] of cathepsins B and L resulted in the degradation of high molecular weight isoforms of tau protein and the production of a 29-kDa tau fragment (tau 29). A tau antibody that is sensitive to the phosphorylated state of its epitopes did not recognize tau proteins or the tau 29 fragment in slices that had been treated with a protein phosphatase inhibitor. This strongly suggests that the tau fragment was located in an extralysosomal compartment accessible to kinases and phosphatases. tau 29 exhibited a significant capacity for binding to microtubules and thus has the potential for interfering with normal tau-tubulin interactions. Three lines of evidence indicated that ZPAD-induced tau proteolysis was mediated by cathepsin D: (a) slices treated with the inhibitor had markedly elevated levels of cathepsin D in both lysosomal and extralysosomal compartments; (b) co-incubation of cathepsin D and tau at neutral pH resulted in a loss of intact tau proteins and production of a 28-kDa fragment; and (c) the lysosomotropic drug chloroquine blocked ZPAD-induced increases in mature cathepsin D, and this was accompanied by a suppression of ZPAD-induced tau proteolysis. Changes in lysosomal hydrolases and cytoskeletal perturbations occur during brain aging. The present results suggest that the enzymatic and structural effects are related and, more specifically, are linked by alterations in the concentration and localization of cathepsin D. The tau fragments with microtubule binding capacity generated by cathepsin D could also be a source for the small polypeptides found in association with age-related pathological features.

Distribution of cathepsin D in human ocular tissue: An immunohistochemical study

Summary It is well established that cathepsin D as a major lysosomal acid protease plays an important role in the catabolism of protein in various ocular tissues. In the retinal pigment epithelium (RPE), cathepsin D is involved in the degradation of shed discs during the renewal process. To date, the immunohistochemical localization and distribution of cathepsin D in human ocular tissue has not been precisely analyzed. In this study, the cellular localization of cathepsin D immunoreactivity was examined at the light microscopic level in healthy donor eyes using the alkaline phosphatase-antialkaline phosphatase (APAAP) technique. Cathepsin D immunoreactivity was found in the cellular cytoplasm of the following human ocular tissues: retinal pigment epithelium; Muller cells; ganglion cells; pigmented and unpigmented epithelium of the ciliary body; iris tissue; epithelium and endothelium of the cornea and lens epithelium. In addition, cathepsin D reaction product was detected in the glial cells of the optic nerve and in the cytoplasm of the capillary endothelium. The localization and distribution of cathepsin D and its possible role among the various ocular tissues are discussed in connection with the underlying physiological and pathophysiological conditions.

Specific immunocytochemical localization of cathepsin E at the ruffled border membrane of active osteoclasts

The immunocytochemical localization of cathepsin E, a non-lysosomal aspartic proteinase, was investigated in rat osteoclasts using the monospecific antibody to this protein. At the light-microscopic level, the preferential immunoreactivity for cathepsin E was found at high levels in active osteoclasts in the physiological bone modeling process. Neighboring osteoblastic cells were devoid of its immunoreactivity. At the electron-microscopic level, cathepsin E was exclusively confined to the apical plasma membrane at the ruffled border of active osteoclasts and the eroded bone surface. Cathepsin E was also concentrated in some endocytotic vacuoles of various sizes in the vicinity of the ruffled border membrane, some of which appeared to be secondary lysosomes containing the phagocytosed materials. These results strongly suggest that this enzyme is involved both in the extracellular degradation of the bone organic matrix and in the intracellular breakdown of the ingested substances in osteoclasts.

Specific immunocytochemical localization of cathepsin E at the ruffled border membrane of active osteoclasts

Specific immunocytochemical localization of cathepsin E at the ruffled border membrane of active osteoclasts

Characterization and localization of cathepsin B proteinases expressed by adult Ancylostoma caninum hookworms

The hookworm Ancylostoma caninum induces human eosinophilic enteritis (EE), probably via allergic responses to its secretions. Cysteine and metallo-proteinases may be the components of these secretions that elicit hypersensitivity reactions. In order to characterize genes encoding cysteine proteinases (CP) secreted by A. caninum, an adult hookworm cDNA library was constructed and screened with a cloned fragment of a hookworm CP gene. This fragment was obtained using consensus oligonucleotide, CP-gene-specific primers in the polymerase chain reaction. cDNAs encoding two CPs were obtained from the library and sequenced. The first gene, AcCP-1, encoded a cathepsin B-like zymogen CP of 343 amino acids (aa), predicted to be processed in vivo into a mature CP of 255 aa. Closest nucleotide identities were to Haemonchus contortus cysteine protease (61%) and to human cathepsin B (60%). The second gene, AcCP-2, encoded a mature CP of 254 aa, that showed 86% identity to AcCP-1, and 58% and 47% identity to bovine cathepsin B and human cathepsin B, respectively. Rabbit antisera raised against recombinant AcCP-1 reacted with esophageal, amphidial and excretory glands in formalin-fixed, paraffin embedded sections of both male and female adult hookworms, and with an antigen of approx. 40 kDa in Western blot analysis of excretory/secretory products from adult hookworms. Together, these immuno-hybridization results strongly suggest that the CP encoded by the AcCP-1 gene is secreted by hookworms. These are the first reported CP genes from hookworms. Proteinases encoded by these genes may be responsible for the CP activity that we have shown previously to be secreted by adult A. caninum.

The Distribution of Cathepsin D in Two Types of Lysosomal or Endosomal Profiles of Rat Hepatocytes as Revealed by Combined Immunocytochemistry and Acid Phosphatase Enzyme Cytochemistry

In the electron micrographs of rat hepatocytes, acid phosphatase (ACPase)-positive profiles were classified as either round or elongate types by image analysis, according to a shape index. The former is typical of spherical lysosomes, and the latter are presumed to be the same structures that we have previously termed nematolysosomes. The localization of cathepsin D in these two types of ACPase-positive profiles was electron microscopically examined by a combination of enzyme cytochemistry for ACPase and postembedding immunocytochemistry for cathepsin D. Gold particles showing antigenic sites for cathepsin D were largely present in ACPase-positive structures, although the labeling intensity of gold particles varied with individual sectional profiles of these structures. Quantitative analysis of the labeling density in the two types of ACPase-positive profiles revealed that the amount of cathepsin D in the elongate-type population was smaller than that in the round-type one. This result suggests that the contents of most elongate ACPase-positive structures are different from those of spherical lysosomes and may be similar to those of endosomes. It was also frequently observed that some of the elongate ACPase-positive profiles labeled with few or no gold particles were fused with round profiles which were heavily labeled with gold particles for cathepsin D. It is possible that such fused profiles may be sites for junctions of the two different transport pathways for ACPase and cathepsin D being delivered to lysosomes. Finally, these elongate ACPase-positive structures seem to be equivalent to late endosomes or a different kind of lysosomes containing lower concentrations of hydrolases.

Overexpression and localization of cathepsin B during the progression of human gliomas

Degradation of the extracellular matrix is a prerequisite for acquisition of the invasive phenotype. Several proteinases released by invading tumor cells appear to participate in the focal degradation of extracellular matrix proteins. Using an enzyme-linked immunosorbent assay, enzymatic assays, Western and Northern blotting techniques, we determined whether increased levels of the cysteine protease cathepsin B correlated with the progression and invasion of human gliomas. The amount of cathepsin B activity and protein content were highest in glioblastomas, lower in anaplastic astrocytomas and lowest in normal brain tissue and low-grade gliomas. There were significantly higher amounts of M(r) 25,000 and 26,000 bands in glioblastoma and anaplastic astrocytoma than in normal brain and low-grade glioma tissue extracts as determined by Western blotting with anti-cathepsin antibodies. In addition, cathepsin B transcripts were overexpressed in anaplastic astrocytoma (about two- to three-fold), in glioblastoma (about eight- to 10-fold), compared with normal brain tissue and low-grade glioma. Immunohistochemical staining for cathepsin B showed intense immunoreactivity in tumor and endothelial cells of glioblastomas and anaplastic astrocytomas but only weak immunoreactivity in low-grade glioma and normal brain tissues. Therefore, we conclude that cathepsin B expression is greatest in highly malignant astrocytomas, especially in glioblastomas, and is correlated with the malignant progression of astrocytomas.

Localization of Cathepsins B and D in the Synovial Lining Cells of the Normal Rat Temporomandibular Joint by Immuno-light and -electron Microscopy.

The localization of cathepsins B and D in the synovial lining cells and distribution of the lining cells containing these cathepsins in the normal rat temporomandibular joint (TMJ) were examined immunocytochemically in thick (8-10μm) and semithin (1μm) cryosections with the avidin-biotin-peroxidase complex method and in ultrathin sections with the gold-labeled IgG method. In the thick sections, strong immunoreactivity for cathepsins B and D probably in the type A cells (not clear at this level), was observed simultaneously in the superficial layer of the synovial membrane. This reactivity was strong at the following portions of the synovial membrane located adjacent to the blood vessels: 1) at the anterior portion and 2) medial-posterior portion facing the upper joint cavity, and 3) at the anterior portion and 4) lateral portion facing the lower joint cavity. In semithin cryosections, strong immunoreactivity for cathepsins B and D was simultaneously found in the type A cells which have numerous pseudopodia and vacuoles, while weak granular immunoreaction products for both cathepsins were also observed in the type B cells. In control sections, no type A or B cells showed immunoreactivity for these cathepsins. In the ultrathin sections, numerous gold particles indicating cathepsins B and D were detected in the lysosomes and phagolysosomes of the type A cells facing the lateral intercellular spaces and joint cavity. In the phagolysosomes, these cathepsins were characteristically co-localized. On the other hand, in the type B cells, a few gold particles were localized only in the lysosomes.Judging from these findings, it is suggested that type A cells predominantly contain cathepsins B and D, and that these cathepsins may be restricted within the cells (lysosomes) without extracellular release in the normal rat TMJ. It is also suggested that materials such as cell debris in the lateral intercellular spaces between the type A cells or in the joint cavity are endocytosed by phagosomes nearby, and are digested by proteolytic enzymes (cathepsins B and D) in the lysosomes. In addition, it is considered that this function in the type A cells is most conspicuous at the anterior portion of the synovial membrane of the normal rat TMJ.

Thrombospondin 1 is a tight-binding competitive inhibitor of neutrophil cathepsin G. Determination of the kinetic mechanism of inhibition and localization of cathepsin G binding to the thrombospondin 1 type 3 repeats.

Thrombospondin 1 was recently shown to bind to and inhibit the activity of neutrophil elastase (Hogg, P. J., Owensby, D. A., Mosher, D. F., Misenheimer, T. M., and Chesterman, C. N. (1993) J. Biol. Chem. 268, 7139-7146). This finding led us to question whether thrombospondin 1 also binds and inhibits the other major serine proteinase of neutrophils, cathepsin G. In a competitive binding assay, cathepsin G bound to thrombospondin 1 reversibly and saturably with a dissociation constant in the low nanomolar range. The kinetic mechanism of inhibition of cathepsin G activity by thrombospondin 1 was determined using the synthetic cathepsin G substrate, Suc-Ala-Ala-Pro-Phe-p-nitroanilide, and is consistent with hyperbolic tight-binding inhibition in which thrombospondin 1 binds cathepsin G and the Michaelis cathepsin G-substrate complex and weakens, but does not abolish, the efficiency of hydrolysis of Suc-Ala-Ala-Pro-Phe-p-nitroanilide. In the presence of 2 mM calcium ions, 2.9 +/- 0.4 mol of cathepsin G interacted with 1 mol of thrombospondin 1 trimer with a site-binding constant of 7.0 +/- 3.5 nM, which reduced the efficiency of hydrolysis of Suc-Ala-Ala-Pro-Phe-p-nitroanilide 8.5 +/- 1.4-fold. A lower limit for the on rate constant of 5 x 10(6) M-1 S-1 was established. The affinity of binding and stoichiometry for the interaction between cathepsin G and thrombospondin 1 was enhanced in the absence of calcium ions. In the presence of EDTA, 5.3 +/- 0.5 mol of cathepsin G interacted with 1 mol of thrombospondin 1 with a site-binding constant of 2.1 +/- 1.6 nM, implying the existence of two binding sites for cathepsin G on each subunit of thrombospondin 1, one or both of which is variably exposed and sensitive to calcium ions. Thrombospondin 1 protected fibronectin from cleavage by cathepsin G and blocked cathepsin G-mediated platelet aggregation. In summary, the binding of cathepsin G to thrombospondin 1 is tight, reversible, and close enough to the active site of cathepsin G to perturb the interactions of a small synthetic substrate and exclude a macromolecular protein substrate and platelets. Using defined proteolytic fragments and different conformers of thrombospondin 1, the binding sites for cathepsin G have been localized to the thrombospondin 1 type 3 repeats.

Role of cathepsin D in the degradation of human serum albumin by peritoneal macrophages and veiled cells in antigen presentation

Murine peritoneal macrophages (PMØ) and veiled cells (VC) isolated from the thoracic duct of irradiated lymphadenectomized (MNLX) mice presented intact human serum albumin (HSA) to stimulated T lymphocytes, but VC were not as effective as PMØ in presenting the antigen. Pepstatin A significantly inhibited the presentation of HSA by VC. Lysates prepared from PMØ degraded [ 125I]HSA at pH 4.0 to peptides as demonstrated by SDS-polyacrylamide-gel electrophoresis and autoradiography. Degradation was inhibited by pepstatin A, suggesting that cathepsis D might be responsible for processing the antigen. In contrast, lysates prepared from VC did not degrade [ 125I]HSA. The localization of cathepsin D, by light microscopy, was examined on cytospins of PMØ and VC by means of a peroxidase antiperoxidase technique (PAP). Cathepsin D was found in vacuoles in the cytoplasm of PMØ and, in some cases, appeared to be bound to some areas of the cell surface, but the enzyme could not be detected in VC.

Localization of a biotinylated cathepsin B oligonucleotide probe in human prostate including invasive cells and invasive edges by in situ hybridization.

The cysteine endopeptidase cathepsin B (CB) can degrade basement membrane (BM) proteins (such as laminin, type IV collagen, and fibronectin) at both acid and neutral pHs suggesting that CB has a role in tumor invasion and distant metastasis. The distribution and intensity of CB protein localization vary in normal prostate, benign prostatic hyperplasia (BPH), and neoplastic prostate. These considerations have led us to examine whether the distribution of CB localization in malignant and normal cells is due to storage or active synthesis of CB. In the present study, we examined the localization patterns of CB at the mRNA level in normal prostate, BPH, and well to moderately differentiated neoplastic prostate, focusing on invasive groups of cells and invasive edges of malignant tumors. We used a 25-base biotinylated oligonucleotide CB cDNA "sense" probe to localize CB message in prostate samples obtained from radical prostatectomies. We have determined that CB is actively synthesized by the epithelia of normal, hyperplastic, and neoplastic prostate including some invasive cells in the invasive edges. In both normal and BPH, CB mRNA was localized predominantly in acinar basal cells with some localization in cuboidal/columnar cells. In contrast, in neoplastic prostate, CB mRNA was localized predominantly in columnar cells and in groups of invasive cells and invasive edges. Thus, in malignant prostate the predominant cell types expressing CB differed from those of the normal prostate and BPH. Analysis of CB mRNA localizations indicated a heterogeneity in staining distribution in prostate cancer with some invasive groups of cells and invasive edges exhibiting CB mRNA and others exhibiting little or no reaction products.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunocytochemical Localization of Cathepsin D in Rat Junctional Epithelium

Localization of cathepsin D was studied in the junctional epithelium (JE) of healthy rat gingivae by immuno-light and -electron microscopy, by means of both the avidin-biotin-peroxidase complex method and a colloidal gold IgG method. At the light-microscopic level, cathepsin D was demonstrated in the JE and oral sulcular epithelium (OSE). Cathepsin D immunoreactivity was remarkable in the coronal portion of the JE and decreased toward its apical portion. However, cathepsin D immunoreactivity in the basal cell layer of the JE was negligible or negative. In the OSE, the granular layer was positive for cathepsin D. In the adjacent connective tissue, many macrophage-like cells (not clear at this level) close to the basal cell layer showed strong immunoreactivity. At the electron microscopic level, cathepsin D was found in the primary lysosomes and trans-cisternae of Golgi apparatus in the JE cells. These lysosomes were often fused together or were fused with cathepsin D-negative intracytoplasmic vacuoles to form secondary lysosomes, which indicated that intracellular digestion may have been in progress. However, neutrophils contained few gold particles based on cathepsin D. It is likely that the amounts of cathepsin D contained in the JE cells and macrophages are larger than those of cathepsin D contained in the neutrophils. These findings provided morphological evidence that JE cells have the same endocytotic capacity as macrophages and neutrophils, and that JE cells participate in the intracellular digestion that is carried out by lysosomal enzymes such as cathepsin D. It is suggested, in addition, that maximum intracellular digestion occurs in the coronal portion of the JE.

Immunelectron microscopic localization of cathepsin B in human exocrine glands

The distribution of the lysosomal enzymes cathepsin B, lysozyme, chymotrypsin, and neutrophil elastase was examined in eccrine, apocrine, and sebaceous glands using a postembedding immunogold labeling procedure. Various amounts of cathepsin B were detected in all glands. Lysozyme, however, was detected in apocrine glands only. The other two lysosomal enzymes were not detectable immunologically. In apocrine and eccrine glands, anti-cathepsin B antibody labeled all secretory granules. In sebaceous glands, only the peripheral layer of cells showed immunological activity for cathepsin B. In apocrine glands, granules containing remnants of cristae were more intensively labeled than those lacking cristae which supports the assumption that both granules are derived from mitochondria by acquiring lysosomal enzymes. The enzymes convert mitochondria to granules with cristae and finally to granules without cristae. Thus the difference in morphology is part of a spectrum of the degradation of mitochondria to granules.

O-264 - Increased expression and localization of cathepsins E and D in vulnerable regions of ischemia-induced rat brain

O-264 - Increased expression and localization of cathepsins E and D in vulnerable regions of ischemia-induced rat brain