Purification and characterization of a cystatin-type cysteine proteinase inhibitor in the human hair shaft

Colocalization of cystatin M/E and its target proteases suggests a role in terminal differentiation of human hair follicle and nail

The cysteine protease inhibitor cystatin M/E is a key regulator of a biochemical pathway that leads to epidermal terminal differentiation by inhibition of its target proteases cathepsin L, cathepsin V, and legumain. Inhibition of cathepsin L is important in the cornification process of the skin, as we have recently demonstrated that cathepsin L is the elusive processing and activating protease for transglutaminase 3, an enzyme that is responsible for crosslinking of structural proteins in cornified envelope formation. Here, we study the localization of all players of this pathway in the human hair follicle and nail unit in order to elucidate their possible role in the biology of these epidermal appendages. We found that cathepsin L and transglutaminase 3 specifically colocalize in the hair bulb and the nail matrix, the regions that provide cells that terminally differentiate to the hair fiber and the nail plate, respectively. Furthermore, transglutaminase 3 also colocalizes with the structural proteins loricrin and involucrin, which are established transglutaminase substrates. These findings suggest that cathepsin L and transglutaminase 3 could be involved in the pathway that leads to terminal differentiation, not only in the epidermis but also in the human hair follicle and nail unit.

Purification and characterization of a cysteine protease inhibitor from chum salmon (Oncorhynchus keta) plasma

A cysteine protease inhibitor (CPI) in chum salmon ( Oncorhynchus keta) plasma (CSP) was detected after performing inhibitory activity staining against papain under nonreducing condition. The CPI was purified from CSP by affinity chromatography with a yield and purification ratio of 0.94% and 30.36-fold, respectively. CSP CPI had a molecular mass of 70 kDa based on the results of SDS-PAGE and Sephacryl S-100 gel filtration. CSP CPI was a glycoprotein based on the periodic acid-Schiff (PAS) staining of the SDS-PAGE gel and classified as a kininogen. CSP CPI was stable in the pH range of 6.0-9.0 with maximal stability at pH 7.0. CSP CPI presented thermal stability at temperatures below 50 degrees C and exhibited maximal activity at temperatures of 20-40 degrees C. CSP CPI was determined to be a noncompetitive inhibitor against papain, with an inhibitor constant (Ki) of 105 nM.

Expression of soluble form carp (Cyprinus carpio) ovarian cystatin in Escherichia coli and its purification

A DNA encoding thioredoxin-mature carp ovarian cystatin (trx-cystatin) fusion protein was ligated into a pET-23a(+) expression vector and then transformed into Escherichia coli AD494(DE3) expression host. After induction by isopropyl beta-D-thiogalactopyranoside, a high level of the soluble form of recombinant trx-cystatin was expressed in the cytoplasm of E. coli. The recombinant trx-cystatin could be purified by Ni(2+)-NTA agarose affinity chromatography. The molecular mass (M) of the recombinant trx-cystatin was approximately 28 kDa composed of recombinant thioredoxin (16 kDa) and recombinant mature carp ovarian cystatin (12 kDa). Both recombinant trx-fused and mature carp ovarian cystatins were stable at pH 6-11. No obvious decrease in activity was observed even after 5 min of incubation at 60 degrees C. They exhibited papain-like protease inhibition activity comparable to that of the mature carp ovarian cystatin, which could inhibit papain and mackerel cathepsins L and L-like, but not cathepsin B.

Cloning of human keratolinin cDNA: keratolinin is identical with a cysteine proteinase inhibitor, cystatin A, and is regulated by Ca2+, TPA, and cAMP

Keratolinin has been described as one of the precursor proteins of cornified cell envelope of keratinocytes. Using rabbit polyclonal anti-human keratolinin antibody, we isolated a cDNA clone of human keratolinin gene from a human Agt11 cDNA expression library that was constructed by random priming from poly(A)+RNA extracted from cultured normal human keratinocytes. Screening by rabbit anti-human keratolinin antibody detected one positive clone (HKL-1). The recombinant 12.5-kDa protein constructed from the clone reacted specifically with the anti-human keratolinin antibody. DNA sequence analysis revealed that HKL-1 clone was 448 bp long, and its putative amino acid sequence was identical with that of a human cysteine proteinase inhibitor, cystatin A. Western blot analysis showed that the commercially available recombinant cystatin A also reacted specifically with the anti-human keratolinin antibody. Northern blot analysis indicated that HKL-1 clone hybridizes with mRNA of about 0.5 kb, consistent with the size of the HKL-1 clone. The keratolinin mRNA was highly expressed in cultured human keratinocytes in high Ca2+ (1 mM); in low Ca2+ (0.05 mM), the keratolinin mRNA expression was significantly lower. Using SV40-transformed human keratinocytes (SVHK cells), we further analyzed the regulation of keratolinin mRNA. In low Ca2+ (0.05 mM), keratolinin mRNA in SVHK cells was marginally detectable. Upon shift to 1 mM calcium, keratolinin mRNA was markedly increased. The upregulation of keratolinin mRNA was also observed by the treatment of SVHK cells with 10 ng TPA per ml or 100 microM forskolin under low calcium conditions (0.05 mM). Our results indicate that keratolinin is identical with cystatin A, a cysteine proteinase inhibitor, and its expression is positively regulated by Ca2+, TPA, and forskolin.

Isolation and amino acid sequence of a cystatin-type cysteine proteinase inhibitor from bovine hoof

A low molecular mass cysteine proteinase inhibitor was found and isolated from bovine hoof. Purification of the inhibitor to homogeneity was performed by carboxymethyl-papain-sepharose affinity and DE-52 ion exchange chromatographies. From 15 g of bovine hoof, 0.25 mg of cysteine proteinase inhibitor was isolated. It had 100 amino acid residues and molecular mass of 11 406 Da, and its N-terminus was blocked. The amino acid sequence of the inhibitor demonstrated high similarity with that of the family 1 group, especially bovine thymus-derived cystatin. Thus, in summary, bovine hoof contains a cystatin-type cysteine proteinase inhibitor, presumably a family 1 cystatin.

Molecules of the cycling hair follicle--a tabulated review

In this review we tabulated molecules which have been experimentally identified to be associated with, or play a role in, hair follicle growth. While compiling these data we were impressed by the fact that this field is only now beginning to be developed in terms of molecular analysis. Ironically, hair was used in some of the earliest molecular approaches to biologic structure (e.g. Astbury and Street, 1931), but the field did not develop from there. From our review we have come to the following conclusions. (1) As indicated by the growing number of reports dealing with follicle-associated molecules in the past 3 years, the field of hair biology has entered a new molecular era. (2) In many reported hair biology studies not enough emphasis has been placed on the fact that the follicle is a dynamic structure. All too often a study is limited to follicles of one particular phase of the cycle or one phase of development. Students in the field have to be more sensitive to the remarkable changes that this deceptively simple structure can undergo during its cycle. (3) Although we have not been able to find any molecules unique to the follicle, some of the structural molecules come close to an ideal tool. It is our impression that even more specific molecule tags will be found. Whether this requires a subtraction library approach or gene mapping of specific mutants is not yet clear. It would appear that the large, diverse family of intermediate filament-associated proteins will prove to be an excellent source of unique follicle-labeling molecules. (4) There is an acute need for molecules which distinguish the phases of the cycle, e.g. telogen from early anagen. Telogen is by far the most difficult phase to identify morphologically since the earliest phase of anagen and the latest phase of catagen may appear structurally like telogen. That these phases are functionally distinguishable must imply a molecular difference. As the number of recognized hair follicle-associated molecules and their interactions increase, it will be essential to assemble libraries of highly specific RNA and antibody probes for localization and mapping studies. We recognize that this review, as written, is imperfect. It is particularly deficient in making any effort towards identifying unifying principles of structure and function. We look forward to returning to this subject within 3 years.(ABSTRACT TRUNCATED AT 400 WORDS)

Isolation of cysteine proteinase inhibitor, cystatin A, from human nails

A cysteine proteinase inhibitor was found in human nail extract treated with 0.01 M Tris HCl buffer, pH 8.0. It had a 2-fold lower and a 4.5-fold higher activity than that of human skin and hair extracts, respectively. From 5.9 g of human nail, 0.1 mg of cysteine proteinase inhibitor was obtained. It was purified by sequential DE-52 ion exchange and carboxymethyl papain affinity chromatography. The purified inhibitor had an apparent molecular mass of 12 kDa as determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis. It was more stable against heat and pH than most other proteins. Immunologically, it had the same antigenicity compared with human epidermal cystatin A. Its N-terminal amino acid sequence showed a mixed form comprising a full-length MIPG sequence a truncated IPGG sequence. This sequence was identical to human cystatin A consisting of 20% of the full-length and 80% of the truncated form. These results showed that human nail also contains cystatin A type cysteine proteinase inhibitor. Nails can be used as a source of cystatin A.