STK11 phospho T189
Function
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. 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).
Isoform 2
Has a role in spermiogenesis.
Involvement in disease
Peutz-Jeghers syndrome
PJS
An autosomal dominant disorder characterized by melanocytic macules of the lips, multiple gastrointestinal hamartomatous polyps and an increased risk for various neoplasms, including gastrointestinal cancer.
None
The disease is caused by variants affecting the gene represented in this entry.
Testicular germ cell tumor
TGCT
A common malignancy in males representing 95% of all testicular neoplasms. TGCTs have various pathologic subtypes including: unclassified intratubular germ cell neoplasia, seminoma (including cases with syncytiotrophoblastic cells), spermatocytic seminoma, embryonal carcinoma, yolk sac tumor, choriocarcinoma, and teratoma.
None
The gene represented in this entry may be involved in disease pathogenesis.
Defects in STK11 are associated with some sporadic cancers, especially lung cancers. Frequently mutated and inactivated in non-small cell lung cancer (NSCLC). Defects promote lung cancerigenesis process, especially lung cancer progression and metastasis. Confers lung adenocarcinoma the ability to trans-differentiate into squamous cell carcinoma. Also able to promote lung cancer metastasis, via both cancer-cell autonomous and non-cancer-cell autonomous mechanisms.
Post-translational modifications
Phosphorylated by ATM at Thr-363 following ionizing radiation (IR). Phosphorylation at Ser-428 by RPS6KA1 and/or some PKA is required to inhibit cell growth. Phosphorylation at Ser-428 is also required during neuronal polarization to mediate phosphorylation of BRSK1 and BRSK2 (By similarity). Phosphorylation by PKC/PRKCZ at Ser-399 in isoform 2 promotes metformin (or peroxynitrite)-induced nuclear export of STK11 and activation of AMPK. UV radiation-induced phosphorylation at Thr-363 mediates CDKN1A degradation (By similarity).
Acetylated. Deacetylation at Lys-48 enhances cytoplasmic localization and kinase activity in vitro.
Sequence Similarities
Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. LKB1 subfamily.
Tissue Specificity
Ubiquitously expressed. Strongest expression in testis and fetal liver.
Cellular localization
- Nucleus
- Cytoplasm
- Membrane
- Mitochondrion
- A small fraction localizes at membranes (By similarity). Relocates to the cytoplasm when bound to STRAD (STRADA or STRADB) and CAB39/MO25 (CAB39/MO25alpha or CAB39L/MO25beta). Translocates to the mitochondrion during apoptosis. PTEN promotes cytoplasmic localization.
- Isoform 2
- Nucleus
- Cytoplasm
- Predominantly nuclear, but translocates to the cytoplasm in response to metformin or peroxynitrite treatment.
Alternative names
LKB1, PJS, STK11, Serine/threonine-protein kinase STK11, Liver kinase B1, Renal carcinoma antigen NY-REN-19, hLKB1
Database links
Other research areas
- Oncology