Human GDF15 (growth differentiation factor 15) protein is a member of the TGFβ family and subject of intense interest as a marker of cellular stress and for its role in metabolism, cancer and pregnancy. Human GDF15 also is functional in mouse studies.
This 25 kDa disulfide-linked dimer is composed of the mature domain of human growth differentiation factor 15 protein. Our recombinant GDF15 protein is expressed in E. coli and exceptionally high purity extensively validated to ensure no trace contamination of related TGFβ family proteins from the mammalian culture systems, which historically led to controversy in the literature.
mouse – 67%
porcine – 67%
rat – 66%
bovine – 66%
GDF15 signals through GRAL and co-receptor RET leading to RET phosphorylation and signalling through the ERK and AKT pathway (reviewed in Emmerson et al., 2018). Commercial sources of GDF15, in particular those purified from mammalian expression systems, have been shown previously to be contaminated with trace amounts of TGFβ. These trace contaminants cause misleading experimental results due to the picomolar or even femtomolar EC50s (Olsen et al., 2017). Here we use a well-characterized SMAD2/3 activation assay to show that there is no contamination from other TGFβ family proteins.
Bioactivity is determined using a luciferase reporter assay in HEK293T cells. Cells are treated (in triplicate) with a serial dilution of GDF15 or Qk001 ActA for 6 hours. Firefly luciferase activity is measured and normalized to the control Renilla luciferase activity. EC50 = 0 pM (no contamination with TGFβ or related growth factors). Data from Qk017 lot #011
GDF15 migrates as a single band at 24 kDa in non-reducing (NR) and 13 kDa as a single monomeric species upon reduction (R). No contaminating protein bands are visible.
Purified recombinant protein (7 µg) was resolved using 15% w/v SDS-PAGE in reduced (+β-mercaptothanol, R) and non-reduced conditions (NR) and stained with Coomassie Brilliant Blue R250. Data from Qk017 lot #010
further quality assays
mass spectrometry: single species with expected mass
analytical reversed-phase: single sharp peak
endotoxin: <0.005 EU/μg protein (below level of detection)
We are a company founded and run by scientists to provide a service and support innovation in stem cell biology and regenerative medicine. All our products are exceptionally high purity, with complete characterisation and bioactivity analysis on every lot.
Growth differentiation factor 15 (GDF-15) is a distant member of the TGFβ superfamily. Its expression is tightly regulated and circulating GDF15 protein in serum is associated with diseases such as cancer, cardiovascular disease, obesity and metabolic disease. GDF15 protein is being recognized as an important biomarker for cellular stress.
Unlike other members of the TGFβ superfamily that cause activation of the SMAD pathway, GDF15 protein signals through GRAL and co-receptor RET leading to RET phosphorylation and signalling through the ERK and AKT pathway (reviewed in Emmerson et al., 2018). Commercial sources of recombinant human GDF15 protein, in particular those purified from mammalian expression, are frequently contaminated with trace amounts of TGFβ and related proteins. These trace contaminants cause misleading experimental results due to the picomolar or even femtomolar EC50s of this family of cytokines2. Please be cautious with your source of recombinant GDF15 protein, our scientists are happy to provide further information, please email email@example.com
We produce our proteins in E. coli with no animal products in our culture or purification processes to ensure there is no contamination from related proteins. In addition, we use a well-characterized SMAD2/3 activation assay to confirm there is no SMAD signalling.