Ultrastructural observations on the enzymatic activity of keratinosomes

González, Luis Fernando; Krawczyk, Walter S.; Wilgram, George F.

doi:10.1016/s0022-5320(76)80067-6

Cited by 28 publications

(9 citation statements)

References 35 publications

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“…Lamellate bodies in Podarcis have shown AP activity, as reported for those of mammals (Weinstok & Wilgram, 1970;Lazarius, Hatcher & Levine, 1975;Gonzales et al, 1976;Menon, Ghadially et al, 1992). Lamellate bodies in Podarcis have shown AP activity, as reported for those of mammals (Weinstok & Wilgram, 1970;Lazarius, Hatcher & Levine, 1975;Gonzales et al, 1976;Menon, Ghadially et al, 1992).…”

Section: Lysosome Involvement During A-keratinizationmentioning

confidence: 68%

“…While in mammals lamellate granules discharge most of their contents and AP into the extracellular space (Weinstock & Wilgram, 1970;Gonzales et al, 1976;Menon, Ghadially et al, 1992), in lepidosaurians most mesos (lamellar) granules are retained intracellularly and scarce lipids are present between a-cells (Landmann, 1980). While in mammals lamellate granules discharge most of their contents and AP into the extracellular space (Weinstock & Wilgram, 1970;Gonzales et al, 1976;Menon, Ghadially et al, 1992), in lepidosaurians most mesos (lamellar) granules are retained intracellularly and scarce lipids are present between a-cells (Landmann, 1980).…”

Section: Lysosome Involvement During A-keratinizationmentioning

confidence: 99%

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Presence of acid phosphatase in the epidermis of the regenerating tail of the lizard (Podarcis muralis) and its possible role in the process of shedding and keratinization

Alibardi

1998

Journal of Zoology

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The activity and distribution of the lysosomal marker enzyme acid phosphatase have been studied in the epidermis during tail regeneration in the lizard Podarcis muralis. This study gives information both on the mechanism of separation of the old from the new epidermal generation and on the involvement of lysosomes in b-and a-keratinization in lepidosaurians. The biochemical analysis shows that the activity of acid phosphatase was higher in the regenerating tail than in the normal tail until the stage of skin shedding at around 25±30 days post-amputation. The enzyme was present in keratinizing layers of epidermis, and particularly in the shedding layer. The shedding layer followed the outline of the regenerating scales beneath the wound in the epidermis showing that lysosomal enzymes are involved in epidermal shedding. The ultrastructural study showed that acid phosphatase was initially localized within the lysosomes but, with the progress of differentiation, it also appeared free within the cytoplasm of the cornifying cells of the shedding complex and of the b-keratinizing cells, and in the intercellular space among them. The role of lysosomal enzymes in the shedding process and their involvement in the mechanism of b-keratinization is discussed. While the process of b-keratinization has an intracellular and extracellular localization of acid phosphatase, the process of a-keratinization shows that most acid phosphatase is localized within the cell. Lysosomes and mesos granules containing acid phosphatase were concentrated in the cytoplasm of differentiating mesos cells. Some mesos granules later discharged their contents into the extracellular space. The a-layer was partially formed in proximal regenerated scales around 30 days post-amputation. Lysosomes appeared to concentrate within pre-keratinizing cells of the a-keratin layer and little reactivity was seen extracellularly.

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Section: Lysosome Involvement During A-keratinizationmentioning

confidence: 68%

Section: Lysosome Involvement During A-keratinizationmentioning

confidence: 99%

Presence of acid phosphatase in the epidermis of the regenerating tail of the lizard (Podarcis muralis) and its possible role in the process of shedding and keratinization

Alibardi

1998

Journal of Zoology

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“…Although the function of this 25K MCG-related protein is presently unknown, it is possible that it represents one of the several known MCG-associated enzymatic activities, including acid hydrolases and phospholipases, and several widely expressed lysosomal enzymes that have been histochemically localized to the intercellular space beneath the stratum corneum (Eisen et al, 1964;Elias et al, 1988;Frienkel and Traczyk, 1983;Gonzalez et al, 1976;Menon et al, 1986;Weinstock and Wilgrarn, 1970;Wolff-Schreiner, 1977). These MCG-associated enzymes are thought to be involved in a number of processes including the postsecretory modification ofMCG lipids converting them into a functional permobility barrier, and/or the degradation of intercellular constituents such as desmosomal components resulting in desquamation.…”

Section: Discussionmentioning

confidence: 99%

“…the process of desquamation in which the terminally differentiated keratinocytes are sloughed off (Elias, 1983). Evidence for this includes the histochemical demonstration of several classes of hydrolytic enzyme activities including acidic hydrolases and phospholipases in MCGs and their discharges (Eisen et al, 1964;Elias et al, 1988;Frienkel and Traczyk, 1983;Gonzalez et al, 1976;Weinstock and Wilgram, 1970;Wolff-Shreiner, 1977). There is also little doubt that some proteins exist in MCGs that play a structural role in maintaining membrane structure and/or modulating the organization of intercellular lamellae.…”

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confidence: 99%

Association of a basic 25K protein with membrane coating granules of human epidermis.

O’Guin

Manabe

Sun

1989

The Journal of Cell Biology

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Abstract. Keratinocytes of the upper granular layers contain unique round-to-oval granules, 100-500 nm in diameter, in their peripheral cytoplasm. These granules (known as membrane coating granules [MCG], or lamellar granules) fuse with the apical cell surface of uppermost granular cells and discharge their contents into the intercellular space, where they are believed to play a role in establishing the permeability barrier of the epidermis and possibly in regulating the orderly desquamation of terminally differentiated keratinocytes. Using two monoclonal antibodies originally prepared against hair follicle antigens, we have identified a 25K epidermal protein in association with both MCG-like granules in the peripheral cytoplasm of granular cells as well as MCG-derived intercellular material. This protein is relatively basic (pI > 8), largely aqueous soluble, methionine deficient, and is relatively abundant in epidermis (comprising up to ",,0.1% of soluble proteins). Its distribution is restricted to the granular layer of keratinized (cornified) stratified squamous epithelia. The identification of this protein component opens new avenues for studying the molecular mechanisms underlying the establishment of permeability barrier and/or regulation of desquamation.

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“…This process is catalysed by copper, takes place within keratinocytes and also occurs at Spearman and Hardy [1975], using a special ultrastructural method. There appear to be enzymes for keratogenesis at the cell membrane and in the intercellular spaces, which provide intercellular cohesion [Gonzalez et al, 1976;Malkinson and Pearson, 1977]. Since Z)(-)penicillamine attaches itself to the cell surface, but does not penetrate the cell [Lyle, 1977], its interference with keratogenesis may occur as follows: (i) as it is a thiol it could dissociate disulphide bonds by 'thioldisulphide exchange'.…”

Section: Discussionmentioning

confidence: 99%

Pemphigus Provoked by <i>D</i>(-)Penicillamine

Ruocco¹,

Luca²,

Pisani³

et al. 1982

Dermatology

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We present the results of our experiments with in vitro tissue cultures of normal human skin, carried out in order to clarify the mechanism(s) by which D(-)penicillamine provokes pemphigus. Various concentrations of D(-)penicillamine were added to the culture medium and produced acantholytic splitting, closely similar to control lesions produced by pemphigus serum, whereas no lesions occurred in controls cultured without the drug. This suggests to us that the pemphigus of D(-)penicillamine is due to biochemical mechanisms and is not mediated by antibodies. Integrating our data with those of previous clinical and experimental studies on idiopathic pemphigus vulgaris leads us to think that the pemphigus antigen(s) might be present in certain structures of the cell membrane of epithelial cells, which are linked with the initial phases of keratin differentiation.

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Ultrastructural observations on the enzymatic activity of keratinosomes

Cited by 28 publications

References 35 publications

Presence of acid phosphatase in the epidermis of the regenerating tail of the lizard (Podarcis muralis) and its possible role in the process of shedding and keratinization

Presence of acid phosphatase in the epidermis of the regenerating tail of the lizard (Podarcis muralis) and its possible role in the process of shedding and keratinization

Association of a basic 25K protein with membrane coating granules of human epidermis.

Pemphigus Provoked by <i>D</i>(-)Penicillamine

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