scholarly journals A type VI collagen-related glycopolypeptide is the major concanavalin A-binding component in pig skin

1989 ◽  
Vol 257 (1) ◽  
pp. 79-86 ◽  
Author(s):  
I A King ◽  
A Tabiowo ◽  
P R Fryer ◽  
F M Pope

The major concanavalin A-binding component in urea/deoxycholate/mercaptoethanol extracts of pig skin was a collagenous disulphide-cross-linked glycopolypeptide with an apparent molecular mass of 150 kDa and a pI of 5.5. Antiserum against the electrophoretically purified glycopolypeptide gave strong dermal staining similar to that seen with fluorescent concanavalin A. Immunocytochemical labelling showed prominent labelling of 3-4 nm dermal microfilaments, particularly those associated with dermal blood vessels and mast cells. Immunoblotting with authentic antiserum indicated that the major skin glycopolypeptide was probably identical with collagen-like glycoprotein, the tissue form of the alpha 1/alpha 2 subunits of type VI collagen. This was confirmed by immunoblotting of authentic type VI collagen from pepsin-treated pig skin. Immunoblotting, metabolic labelling with [3H]glucosamine and immune precipitation showed that an immunoreactive collagenous glycopolypeptide was synthesized and secreted by cultured pig skin fibroblasts. The results suggest that type VI collagen is the major concanavalin A-binding component in pig skin.

1987 ◽  
Vol 105 (6) ◽  
pp. 3053-3063 ◽  
Author(s):  
I A King ◽  
A Tabiowo ◽  
P R Fryer

The major concanavalin A (Con A)-binding component in urea/deoxycholate/mercaptoethanol extracts from pig ear epidermis had an apparent Mr of 78 kD. In indirect immunofluorescence affinity-purified polyclonal antibodies against this glycopolypeptide strongly stained the surface of suprabasal cells in the epidermis of pig and human skin. Immunocytochemical labeling with gold-labeled second antibody localized this staining to externally disposed, trypsin-sensitive components of desmosomes. Western blotting showed that the 78-kD glycopolypeptide was immunologically related to several other Con A-binding components in pig epidermis. Immunoreactive components with Mr of 115 and 100 kD were membrane-bound, appeared to be susceptible to trypsin in intact epidermis, and were absent from the stratum corneum. Immunoreactive components of lower Mr (78-44 kD) were not membrane-bound, were resistant to trypsin in intact tissue, and were present predominantly in the keratinized layers of pig epidermis. The 115-44-kD glycopolypeptides were also recognized by antisera raised against desmoglein II/desmocollin glycoproteins isolated from bovine spinous layer desmosomes. In addition, these antisera reacted with 120- and 105-kD bands that were apparently not recognized by the anti-78-kD glycopolypeptide antiserum in immunoblotting. In immune precipitation the anti-78-kD glycopolypeptide and antidesmoglein II/desmocollin antisera precipitated comparable amounts of the radioiodinated 78-44-kD components. Both antisera also precipitated the 120- and 105-kD components although the anti-78-kD glycopolypeptide serum was less effective. Little reaction with the 115- and 105-kD components was observed in immune precipitation with either serum. Proteolytic peptide mapping confirmed that the various immunoreactive glycopolypeptides were biochemically as well as immunologically related. The results suggest that terminal differentiation in pig epidermis is accompanied by the orderly degradation of desmoglein II/desmocollin glycoproteins resulting in the accumulation of 78-44-kD glycopolypeptides in the stratum corneum. These glycopolypeptides may represent functionally important nonmembranous domains of cell-adhesion molecules in desmosomes.


1985 ◽  
Vol 260 (20) ◽  
pp. 11149-11159 ◽  
Author(s):  
M A Gibson ◽  
E G Cleary
Keyword(s):  

1974 ◽  
Vol 9 (5) ◽  
pp. 903-908 ◽  
Author(s):  
W. A. Hook ◽  
S. F. Dougherty ◽  
J. J. Oppenheim
Keyword(s):  

1964 ◽  
Vol 12 (7) ◽  
pp. 538-544 ◽  
Author(s):  
MAX WACHSTEIN ◽  
ELIZABETH MEISEL

By using an improved benzidine technique, peroxidase activity can be demonstrated in various locations in mammalian tissues. A relatively formalin resistant enzyme is found in hemoglobin and is also associated with mitochondria of striated muscle and heart. A somewhat less formalin resistant peroxidase occurs in the granules of myeloid and mast cells. A relatively formalin sensitive peroxidase is present in a number of additional locations, e.g. the acinar cells in thyroid and salivary gland, the medulla of the kidney, in hair follicles of the guinea pig skin and Kupffer cells of the liver.


1986 ◽  
Vol 233 (1) ◽  
pp. 65-72 ◽  
Author(s):  
S H Cheng ◽  
S Malcolm ◽  
S Pemble ◽  
B Winchester

Human liver alpha-D-mannosidases A and B were purified 11 500-fold and 2000-fold respectively. Both showed microheterogeneity when analysed by isoelectric focusing. Alpha-D-Mannosidases A and B are immunologically identical but differ in their range of pI values, molecular masses, uptake into fibroblasts and subunit compositions. Alpha-D-Mannosidase A consists of equimolar proportions of subunits of molecular masses 62 kDa and 26 kDa, which are linked by disulphide bridges in the intact enzyme. Alpha-D-Mannosidase B also contains a small subunit, of molecular mass 26 kDa, and a variable mixture of larger subunits, of molecular masses 58 kDa and 62 kDa. The 62 kDa and 58 kDa subunits, but not the 26 kDa one, contain concanavalin A-recognizing glycans. The 58 kDa subunit has a lower pI, contains less high-mannose glycans but probably contains more mannose 6-phosphate than the 62 kDa subunit. It is postulated that the differences in structure and properties of alpha-D-mannosidases A and B are due to differences in the state of processing of the large subunit. This suggestion is consistent with a single locus on chromosome 19 for lysosomal alpha-D-mannosidase.


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