Tsukushi/TSK in Human Colon Cancer Tissue. Tsukushi/TSK was detected in immersion fixed paraffin-embedded sections of human colon cancer tissue using Goat Anti-Human Tsukushi/TSK Antigen Affinity-purified Polyclonal Antibody (Catalog # AF3940) at 10 µg/mL overnight at 4 °C. Before incubation with the primary antibody, tissue was subjected to heat-induced epitope retrieval using Antigen Retrieval Reagent-Basic (Catalog # CTS013). Tissue was stained using the Anti-Goat HRP-DAB Cell & Tissue Staining Kit (brown; Catalog # CTS008) and counterstained with hematoxylin (blue). Lower panel shows a lack of labeling when primary antibodies are omitted and tissue is stained only with secondary antibody followed by incubation with detection reagents. Specific staining was localized to smooth muscle. View our protocol for Chromogenic IHC Staining of Paraffin-embedded Tissue Sections.
Preparation and Storage
Sterile PBS to a final concentration of 0.2 mg/mL.
The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below. *Small pack size (SP) is shipped with polar packs. Upon receipt, store it immediately at -20 to -70 °C
Stability & Storage
Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
12 months from date of receipt, -20 to -70 °C as supplied.
1 month, 2 to 8 °C under sterile conditions after reconstitution.
6 months, -20 to -70 °C under sterile conditions after reconstitution.
TSK, also known as Tsukushi, is an atypical member of the small leucine-rich proteoglycan (SLRP) family of extracellular matrix proteins (1, 2). All contain leucine-rich repeats (LRR) flanked by conserved cysteines, but the C-terminus of TSK resembles the structure of nyctalopin and chondroadherin rather than class I‑III SLRPs (1). The human TSK cDNA encodes a 16 amino acid (aa) signal sequence and a 337 aa secreted (presumably glycosylated) protein that contains nine LRR (2). Proteoglycan modification of TSK has not been shown. SLRP-like activity or expression of TSK has been identified in several contexts. TSK mRNA is upregulated by estrogen treatment in breast cancer cell lines, and so is proposed to be involved in hormonally regulated extracellular matrix remodeling (2). TSK is upregulated along with bone markers in Vitamin K2-treated osteosarcoma cell lines, mediated by the pregnane X receptor, PXR (3). TSK was also shown to contribute to vitamin K2-mediated enhancement of collagen accumulation. Other SLRPs have been shown to form a protective coat around collagen fibrils, shielding them from proteolysis (4). In rats, expression of TSK in liver, intestines and islets of Langerhans resembles the pattern of Glut2 (5). TSK transcription is upregulated by both estrogen and insulin in hepatocytes. In Xenopus and chick embryos, TSK is expressed in the middle primitive streak, where it binds and antagonizes BMP-4 and promotes dorsalization and formation of the neural crest and the primitive organizer (6, 7). Xenopus TSK also binds the extracellular region of delta-1, modulating Notch activity (7). Human TSK shows 87%, 86%, 86%, 85%, 52% and 50% aa identity with canine, mouse, rat, bovine, chick, and Xenopus TSK, respectively, with the highest identity in the first four LRR.
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Ohta, K. et al. (2004) Dev. Cell 7:347.
Kuriyama, S. et al. (2006) Development 133:75.
Tsukushin Leucine-rich Repeat Containing Protein 54
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