|Datasheet||Specific References||Reviews||Related Products||Protocols|
|Human Cell lysate that Human SPARC / Osteonectin transfected / overexpressed for Western blot (WB) positive control. The whole cell lysate is provided in 1X Sample Buffer (1X modified RIPA buffer+1X SDS loading buffer).|
|A DNA sequence encoding the human SPARC (NP_003109.1) precursor (Met 1-Ile 303) with a carboxy-terminal polyhistidine tag was expressed.|
|The secreted recombinant human SPARC consists of 297 amino acids with the predicted molecular mass of 34 kDa. As a result of glycosylation, rhSPARC migrates as an approximately 45 kDa band in SDS-PAGE under reducing conditions.|
|Cell lysate was prepared by homogenization in ice-cold modified RIPA Lysis Buffer with cocktail of protease inhibitors (Sigma). Cell debris was removed by centrifugation. Protein concentration was determined by Bradford assay (Bio-Rad protein assay, Microplate Standard assay). The cell lysate was boiled for 5 min in 1 x SDS loading buffer (50 mM Tris-HCl pH 6.8, 12.5% glycerol, 1% sodium dodecylsulfate, 0.01% bromophenol blue) containing 5% b-mercaptoethanol, and lyophilized.|
|Modified RIPA Lysis Buffer: 50 mM Tris-HCl pH 7.4, 150 mM NaCl, 1mM EDTA, 1% Triton X-100, 0.1% SDS, 1% Sodium deoxycholate, 1mM PMSF.|
|12.5% SDS-PAGE Stained with Coomassie Blue after protein purification.|
|Samples are stable for up to twelve months from date of receipt.|
|1. Centrifuge the tube for a few seconds and ensure the pellet at the bottom of the tube. 2. Re-dissolve the pellet using 200μL pure water and boil for 2-5 min. 3. Store the lyophilized cell lysate at 4℃. After re-dissolution, recommend to aliquot it into smaller quantities and store at -80℃.|
|1 X Sample Buffer (1 X modified RIPA buffer+1 X SDS loading buffer).|
|Store at 4℃. After re-dissolution, aliquot and store at -80℃.|
|Western blot (WB): Use at an assay dependent dilution.|
Other Applications: Not tested.
Optimal dilutions/concentrations should be determined by the end user.
Secreted protein acidic and rich in cysteine (SPARC), also known as Osteonectin (ON), is a member of the SPARC family. SPARC consists of three domains: a EF-hand domain, a follistatin-like domain and a Kazal-like domain, and each of which has independent activity and unique properties. The activity of SPARC is context- and cell-type-dependent, which is highlighted by the fact that SPARC has shown seemingly contradictory effects on tumor progression in both clinical correlative studies and in animal models. The location of SPARC in the nuclear matrix of certain proliferating cells, but only in the cytosol of postmitotic neurons, indicates potential functions of SPARC as a nuclear protein, which might be involved in the regulation of cell cycle progression and mitosis. It functions not only to modulate cell-cell and cell-matrix interactions, but its de-adhesive and growth inhibitory properties in non-transformed cells have led to studies to assess its role in cancer. Its divergent actions reflect the complexity of this protein, because in certain types of cancers, such as melanomas and gliomas, SPARC is associated with a highly aggressive tumor phenotype, while in others, mainly ovarian, neuroblastomas and colorectal cancers, SPARC may function as a tumor suppressor. Recent studies have also demonstrated a role for SPARC in sensitizing therapy-resistant cancers. Notably, SPARC is linked to human obesity.