Disease relevance of SPOCK1

• We propose that N-Tes-Delta 122, which is resistant to testican 2, may have therapeutic potential as a barrier against glioma invasion [1].
• This testican messenger RNA is not detected in normal quiescent astrocytes, but is up regulated when these cells are activated in response to injury such as cerebral stroke [2].
• As MT1-MMP mediated pro-MMP-2 activation is of significance for cartilage destruction in osteoarthritis, we studied the expression and localization of testican-1 in human articular cartilage [3].
• Yancy and Spock (1967) reviewed 31 reported cases of spontaneous chylothorax which occurred in the first 2 months of life and noted that male infants were affected twice as commonly as females [4].

Psychiatry related information on SPOCK1

• Parkinson was one of the first to write on child-rearing practices and in this context antedated Benjamin Spock by 150 years [5].

High impact information on SPOCK1

• The TIC-1 variant is activated by adenine and inhibited by folic acid to the same extent as the type-A enzyme, while the stimulation of the activity of the TIC-1 enzyme by hypoxanthine and the inhibition of it by uric acid is similar to that for the B enzyme [6].
• Binding of testican 2 to N-Tes deposited on collagen allowed migration of cells expressing MT1-MMP [1].
• Testican family proteins are putative extracellular heparan/chondroitin sulfate proteoglycans of unknown function [1].
• These results suggest that abundant distribution of testican 2 may contribute to glioma invasion by inactivating other testican family members including N-Tes, which all inhibit MT-MMPs [1].
• Unlike wild-type N-Tes, N-Tes-Delta 122 did not bind to testican 2, and, thus, expression of testican 2 did not recover cell migration blocked by N-Tes-Delta 122 [1].

Biological context of SPOCK1

• The SPOCK gene spans at least 70 kb and is composed of 11 exons: the first half of the gene is dramatically expanded, but the second half is more compact [7].
• This is much larger than the calculated molecular weight of the encoded polypeptide, suggesting glycosylation of this plasma protein, and large forms of recombinant testican produced in culture were found to include chondroitin sulfate [8].
• An osteonectin-like domain, a Kazal-like sequence and a 46-amino-acid motif around a Cys-Trp-Cys-Val peptide encountered in cell-surface antigens, cell-adhesion molecules and growth-factor-binding proteins are distributed within the testican protein core [9].
• Firstly, the steric fit between the interfaces of testican domain and cathepsin L is stabilised by numerous favourable forces, while no such interactions are evident in the complex with cathepsin K, and repulsive interactions even prevent access of the domain to the active site of papain [10].
• Breast-feeding, bottle-feeding and Dr. Spock: the shifting context of choice [11].

Anatomical context of SPOCK1

• Since testican is expressed by human endothelial cells and includes a signal sequence, it was our hypothesis that testican protein would be present in blood [8].
• Testican is the progenitor of the unique heparan/chondroitin-sulfate-bearing peptide present in human seminal plasma, a feature which might confer additional potentialities to this hybrid proteoglycan [9].
• Testican-1 is a highly conserved, multidomain proteoglycan that is most prominently expressed in the thalamus of the brain, and is upregulated in activated astroglial cells of the cerebrum [12].
• We demonstrate that testican inhibits attachment of Neuro-2a cells and their ability to form neurite extensions [2].
• By immunolocalization, testican-1 protein could be detected in chondrocytes predominantly of the superficial and transitional zones [3].

Associations of SPOCK1 with chemical compounds

• SPOCK, previously identified as testican, is a modular proteoglycan that carries both chondroitin and heparan sulfate glycosaminoglycan side chains [7].
• One testican domain has strong homology to thyropin-type cysteine protease-inhibitors [8].
• Three differential expressed sequences that appear to be upregulated in the presence of testosterone show significant homology to the cDNAs of L-plastin and one to the cDNA of testican [13].

Physical interactions of SPOCK1

• 2. At neutral pH, testican-1 also stabilizes cathepsin L, slowing pH-induced denaturation and allowing the protease to remain active longer, although the rate of proteolysis is reduced [14].

Regulatory relationships of SPOCK1

• Human proteoglycan testican-1 inhibits the lysosomal cysteine protease cathepsin L [14].

Other interactions of SPOCK1

• One-step purification was achieved by affinity chromatography on either a monoclonal antibody (TIC-1) column or an IL-2 column, with a final yield of approximately 5 mg/L of culture supernatant [15].
• We present here some properties of the Tg-1 domain of human testican, a modularly organised proteoglycan secreted mainly by brain cells, the exact in vivo function of which is not yet clear [10].
• Testican, therefore, blocks attachment sites on cultureware and may also block attachment sites in the extracellular matrix of the brain [2].

Analytical, diagnostic and therapeutic context of SPOCK1

• These comparisons identified a candidate MeCP2 target gene, SPOCK1, downregulated in two independent microarray experiments, but its expression was not altered by quantitative RT-PCR analysis on brain tissues from a RTT mouse model [16].
• In situ hybridization showed that neurons are a major source of all of the testican family members in the normal brain [1].
• The extracellular calcium-binding (EC) module of human testican (115 residues) was obtained in native form by recombinant production in mammalian cell culture and thus shown to represent an independently folding domain [17].
• Testican-1 protein was localized by immunohistochemistry in human osteoarthritic cartilage samples, in human fetal knee joint, and in knees from mice [3].

References