CARDIOMETABOLIC

Gene
STK11

Uniprot
Q15831

Protein
Serine/threonine-protein kinase STK11

See alternative names

Liver kinase B1,
Renal carcinoma antigen NY-REN-19

Uniprot Function Description

Has a role in spermiogenesis.

Tumor suppressor serine/threonine-protein kinase that controls the activity of AMP-activated protein kinase (AMPK) family members, thereby playing a role in various processes such as cell metabolism, cell polarity, apoptosis and DNA damage response. Acts by phosphorylating the T-loop of AMPK family proteins, thus promoting their activity: phosphorylates PRKAA1, PRKAA2, BRSK1, BRSK2, MARK1, MARK2, MARK3, MARK4, NUAK1, NUAK2, SIK1, SIK2, SIK3 and SNRK but not MELK. Also phosphorylates non-AMPK family proteins such as STRADA, PTEN and possibly p53/TP53. Acts as a key upstream regulator of AMPK by mediating phosphorylation and activation of AMPK catalytic subunits PRKAA1 and PRKAA2 and thereby regulates processes including: inhibition of signaling pathways that promote cell growth and proliferation when energy levels are low, glucose homeostasis in liver, activation of autophagy when cells undergo nutrient deprivation, and B-cell differentiation in the germinal center in response to DNA damage. Also acts as a regulator of cellular polarity by remodeling the actin cytoskeleton. Required for cortical neuron polarization by mediating phosphorylation and activation of BRSK1 and BRSK2, leading to axon initiation and specification. Involved in DNA damage response: interacts with p53/TP53 and recruited to the CDKN1A/WAF1 promoter to participate in transcription activation. Able to phosphorylate p53/TP53; the relevance of such result in vivo is however unclear and phosphorylation may be indirect and mediated by downstream STK11/LKB1 kinase NUAK1. Also acts as a mediator of p53/TP53-dependent apoptosis via interaction with p53/TP53: translocates to the mitochondrion during apoptosis and regulates p53/TP53-dependent apoptosis pathways. In vein endothelial cells, inhibits PI3K/Akt signaling activity and thus induces apoptosis in response to the oxidant peroxynitrite (in vitro). Regulates UV radiation-induced DNA damage response mediated by CDKN1A. In association with NUAK1, phosphorylates CDKN1A in response to UV radiation and contributes to its degradation which is necessary for optimal DNA repair (PubMed:25329316).

Precision

Precision (repeatability) is calculated from linearized NPX values over LOD.

Within run precision Coefficient of Variation (CV)
10%
Between run precision Coefficient of Variation (CV)
21%

Analytical measuring range

The technical data reported below refers to the measured value in the in vitro validation assays run using known concentrations of recombinant antigen. Please note that these figures are for reference only and CANNOT be used to convert NPX values to absolute concentrations for proteins measured in plasma or serum samples.

LOD (pg/ml)
390.6
LLOQ (pg/ml)
781.3
ULOQ (pg/ml)
400000
Hook (pg/ml)
800000
Range (log10)
2.7

Dilution factor

For optimal assay readout, Olink Explore is run using different dilutions of the original samples (undiluted, 1:10, 1:100 or 1:1000). The dilution factor for this assay is noted below and should be taken into account when estimating the appropriate addressable biological concentration of the protein based on the in vitro validation data.

Dilution factor
1:1

Sensitivity plot

The calibrator curve shown below visualizes the analytical measuring range data based on in vitro measurement of recombinant antigen. Please note that this is shown for reference only and CANNOT be used to convert NPX values to absolute concentrations for proteins measured in plasma or serum samples. The vertical dotted lines represent LLOQ and ULOQ respectively, and the horizontal line indicates the LOD. The y-axis shows NPX above background, which is defined as the median of negative control measurements and used to define the expected background level (zero).

Sample distribution plot

The plot below shows the levels of protein measured in a number of commercial plasma samples. Healthy subjects are shown in blue and samples obtained from patients with a range of diseases are shown in red. The latter include inflammatory, cardiovascular, autoimmune & neurological diseases, as well as cancer. The data is shown to give a general idea of the sort of NPX range to expect, but cannot cover all potential levels that may be seen in clinical samples. The y-axis shows NPX above background, which is defined as the median of negative control measurements and used to define the expected background level (zero).