Cathepsins H (CTSH), L (CTSL), B (CTSB) and S (CTSS) are papain family
cysteine proteinases involved in a variety of physiologic processes such as
proenzyme activation, enzyme inactivation, antigen presentation, hormone
maturation, tissue remodeling, and bone matrix resorption.
NCBI Summary:
The protein encoded by this gene is a lysosomal cysteine proteinase important in the overall degradation of lysosomal proteins. It is composed of a dimer of disulfide-linked heavy and light chains, both produced from a single protein precursor. The encoded protein, which belongs to the peptidase C1 protein family, can act both as an aminopeptidase and as an endopeptidase. Increased expression of this gene has been correlated with malignant progression of prostate tumors. Two transcript variants encoding different isoforms have been found for this gene.
General function
Enzyme, Hydrolase, Peptidase/Protease
Comment
Cellular localization
Secreted, Cytoplasmic
Comment
Ovarian function
Follicle atresia
Comment
Expression regulated by
Comment
Ovarian localization
Oocyte, Theca
Comment
S. Oksjoki reported the differential expression patterns of cathepsins B, H, K, L and S in the mouse ovary.
Cathepsins B, H, K, L and S belong to a family of lysosomal cysteine proteinases which participate in a variety of proteolytic processes, including degradation of extracellular matrix. Although the presence of cathepsin mRNAs in the ovary has been reported earlier, very little information is available on their temporospatial expression. In the present study, Northern analysis revealed cyclic changes in the mRNA levels for cathepsins B, H, K, L and S during the 4-day oestrous cycle in the mouse ovary. Immunohistochemical localization revealed distinct expression patterns suggesting different functions for the cathepsins studied. Strong cathepsin H staining was sharply defined in theca externa which also stained for cathepsins K and S. Corpus luteum was the predominant location of cathepsin L. The distribution of cathepsin S resembled that of cathepsin L. The developing oocyte stained positive for all cathepsins. In-situ hybridization confirmed the differential production of cathepsin mRNAs by granulosa, thecal and luteal cells. These complex temporal and spatial expression patterns at different stages of the oestrous cycle and follicular development suggest divergent functions for specific cathepsins in follicular development, growth and rupture.