Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.64 (proteinase K)
 4,071 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The R- cell line is a 3T3-like cell line originating from mouse embryos with a homozygous disruption of the type 1 insulin-like growth factor receptor (IGF-IR) genes. Although R- cells cannot grow at all in serum-free medium (SFM) supplemented by several known growth factors, either singly or in combination, they are able to grow in 10% serum, albeit at a reduced rate. These findings suggested that serum contains an unknown, or unidentified, growth factor that can promote cell growth even in cells devoid of IGF-IRs. In an effort to identify such growth factor, we searched, using R- cells, for a growth and DNA synthesis stimulating activity in SFM conditioned by different cell lines. We found that the BRL-3A cell line secreted an activity capable of stimulating DNA synthesis and cell proliferation in R- cells. This activity (which is concentration-dependent) can be collected and concentrated by ultrafiltration, it is heat-labile, proteinase K-sensitive and has a size larger than 10 kDa. Because of the resistance of R1 cells to stimulation by known growth factors, we believe that this activity is due to a novel polypeptide secreted by BRL-3A cells. Further characterization of the active component(s) is in progress.
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PMID:A novel growth stimulating activity from BRL-3A cell conditioned medium. 945 20

Seven secretory mammalian kexin-like subtilases have been identified that cleave a variety of precursor proteins at monobasic and dibasic residues. The recently characterized pyrolysin-like subtilase SKI-1 cleaves proproteins at nonbasic residues. In this work we describe the properties of a proteinase K-like subtilase, neural apoptosis-regulated convertase 1 (NARC-1), representing the ninth member of the secretory subtilase family. Biosynthetic and microsequencing analyses of WT and mutant enzyme revealed that human and mouse pro-NARC-1 are autocatalytically and intramolecularly processed into NARC-1 at the (Y,I)VV(V,L)(L,M) downward arrow motif, a site that is representative of its enzymic specificity. In vitro peptide processing studies andor Ala substitutions of the P1-P5 sites suggested that hydrophobicaliphatic residues are more critical at P1, P3, and P5 than at P2 or P4. NARC-1 expression is highest in neuroepithelioma SK-N-MCIXC, hepatic BRL-3A, and in colon carcinoma LoVo-C5 cell lines. In situ hybridization and Northern blot analyses of NARC-1 expression during development in the adult and after partial hepatectomy revealed that it is expressed in cells that have the capacity to proliferate and differentiate. These include hepatocytes, kidney mesenchymal cells, intestinal ileum, and colon epithelia as well as embryonic brain telencephalon neurons. Accordingly, transfection of NARC-1 in primary cultures of embryonic day 13.5 telencephalon cells led to enhanced recruitment of undifferentiated neural progenitor cells into the neuronal lineage, suggesting that NARC-1 is implicated in the differentiation of cortical neurons.
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PMID:The secretory proprotein convertase neural apoptosis-regulated convertase 1 (NARC-1): liver regeneration and neuronal differentiation. 1255 33