STK11

Serine/threonine kinase 11 (STK11) also known as liver kinase B1 (LKB1) or renal carcinoma antigen NY-REN-19 is a protein kinase that in humans is encoded by the STK11 gene.[5]

STK11
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 2WTK, 4ZDR
Identifiers
Aliases	STK11, LKB1, PJS, hLKB1, serine/threonine kinase 11
External IDs	OMIM: 602216 MGI: 1341870 HomoloGene: 393 GeneCards: STK11
Gene location (Human) Chr. Chromosome 19 (human)[1] Band 19p13.3 Start 1,177,558 bp[1] End 1,228,431 bp[1]
Gene location (Mouse) Chr. Chromosome 10 (mouse)[2] Band 10|10 C1 Start 80,115,803 bp[2] End 80,130,682 bp[2]
RNA expression pattern More reference expression data
Gene ontology Molecular function • transferase activity • nucleotide binding • LRR domain binding • protein kinase activity • p53 binding • protein kinase activator activity • metal ion binding • kinase activity • protein serine/threonine kinase activity • GO:0001948 protein binding • ATP binding • magnesium ion binding Cellular component • cytoplasm • membrane • mitochondrion • extracellular exosome • TCR signalosome • cell nucleus • nucleoplasm • cytosol Biological process • response to ionizing radiation • positive regulation of transforming growth factor beta receptor signaling pathway • dendrite extension • TCR signalosome assembly • axonogenesis • glucose homeostasis • positive regulation of autophagy • phosphorylation • negative regulation of lipid biosynthetic process • positive regulation of axonogenesis • cellular response to DNA damage stimulus • regulation of dendrite morphogenesis • autophagy • protein phosphorylation • Golgi localization • regulation of Wnt signaling pathway • vasculature development • anoikis • cellular response to UV-B • negative regulation of cell growth • regulation of cell growth • cell cycle arrest • tissue homeostasis • establishment of cell polarity • positive thymic T cell selection • positive regulation of peptidyl-tyrosine phosphorylation • regulation of protein kinase B signaling • canonical Wnt signaling pathway • intrinsic apoptotic signaling pathway by p53 class mediator • autophosphorylation • cell cycle • negative regulation of epithelial cell proliferation involved in prostate gland development • T cell receptor signaling pathway • spermatogenesis • activation of protein kinase activity • negative regulation of TORC1 signaling • negative regulation of cell proliferation • positive regulation of protein localization to nucleus • apoptotic process • regulation of signal transduction by p53 class mediator • nervous system development • peptidyl-serine phosphorylation • peptidyl-threonine phosphorylation • cell differentiation • positive regulation of protein serine/threonine kinase activity • protein dephosphorylation • negative regulation of canonical Wnt signaling pathway • negative regulation of cold-induced thermogenesis Sources:Amigo / QuickGO
Orthologs
Species	Human	Mouse
Entrez	6794	20869
Ensembl	ENSG00000118046	ENSMUSG00000003068
UniProt	Q15831	Q9WTK7
RefSeq (mRNA)	NM_000455	NM_001301853 NM_001301854 NM_011492
RefSeq (protein)	NP_000446	NP_001288782 NP_001288783 NP_035622
Location (UCSC)	Chr 19: 1.18 – 1.23 Mb	Chr 10: 80.12 – 80.13 Mb
PubMed search	[3]	[4]
Wikidata
View/Edit Human View/Edit Mouse

Expression

Testosterone and DHT treatment of murine 3T3-L1 or human SGBS adipocytes for 24 h significantly decreased the mRNA expression of LKB1 via the androgen receptor and consequently reduced the activation of AMPK by phosphorylation. In contrast, 17β-estradiol treatment increased LKB1 mRNA, an effect mediated by oestrogen receptor alpha.[6]

However, in ER-positive breast cancer cell line MCF-7, estradiol caused a dose-dependent decrease in LKB1 transcript and protein expression leading to a significant decrease in the phosphorylation of the LKB1 target AMPK. ERα binds to the STK11 promoter in a ligand-independent manner and this interaction is decreased in the presence of estradiol. Moreover, STK11 promoter activity is significantly decreased in the presence of estradiol.[7]

Function

The STK11/LKB1 gene, which encodes a member of the serine/threonine kinase family, regulates cell polarity and functions as a tumour suppressor.

LKB1 is a primary upstream kinase of adenosine monophosphate-activated protein kinase (AMPK), a necessary element in cell metabolism that is required for maintaining energy homeostasis. It is now clear that LKB1 exerts its growth suppressing effects by activating a group of ~14 other kinases, comprising AMPK and AMPK-related kinases. Activation of AMPK by LKB1 suppresses growth and proliferation when energy and nutrient levels are scarce. Activation of AMPK-related kinases by LKB1 plays vital roles maintaining cell polarity thereby inhibiting inappropriate expansion of tumour cells. A picture from current research is emerging that loss of LKB1 leads to disorganization of cell polarity and facilitates tumour growth under energetically unfavorable conditions.

Loss of LKB1 activity is associated with highly aggressive HER2+ breast cancer.[8] HER2/neu mice were engineered for loss of mammary gland expression of Lkb1 resulting in reduced latency of tumorgenesis. These mice developed mammary tumors that were highly metabolic and hyperactive for MTOR. Pre-clinical studies that simultaneously targeted mTOR and metabolism with AZD8055 (inhibitor of mTORC1 and mTORC2) and 2-DG, respectively inhibited mammary tumors from forming.[9] Mitochondria function In control mice that did not have mammary tumors were not affected by AZD8055/2-DG treatments.

LKB1 catalytic deficient mutants found in Peutz-Jeghers Syndrome activate the expression of cyclin D1 through recruitment to response elements within the promoter of the oncogene. LKB1 catalytically deficient mutants have oncogenic properties.[10]

Clinical significance

Germline mutations in this gene have been associated with Peutz–Jeghers syndrome, an autosomal dominant disorder characterized by the growth of polyps in the gastrointestinal tract, pigmented macules on the skin and mouth, and other neoplasms.[11][12][13] However, the LKB1 gene was also found to be mutated in lung cancer of sporadic origin, predominantly adenocarcinomas.[14] Further, more recent studies have uncovered a large number of somatic mutations of the LKB1 gene that are present in cervical, breast,[8] intestinal, testicular, pancreatic and skin cancer.[15][16]

Activation

LKB1 is activated allosterically by binding to the pseudokinase STRAD and the adaptor protein MO25. The LKB1-STRAD-MO25 heterotrimeric complex represents the biologically active unit, that is capable of phosphorylating and activating AMPK and at least 12 other kinases that belong to the AMPK-related kinase family. Several novel splice isoforms of STRADα that differentially affect LKB1 activity, complex assembly, subcellular localization of LKB1 and the activation of the LKB1-dependent AMPK pathway.[17]

Structure

The crystal structure of the LKB1-STRAD-MO25 complex was elucidated using X-ray crystallography,[18] and revealed the mechanism by which LKB1 is allosterically activated. LKB1 has a structure typical of other protein kinases, with two (small and large) lobes on either side of the ligand ATP-binding pocket. STRAD and MO25 together cooperate to promote LKB1 active conformation. The LKB1 activation loop, a critical element in the process of kinase activation, is held in place by MO25, thus explaining the huge increase in LKB1 activity in the presence of STRAD and MO25 .

Splice variants

Alternate transcriptional splice variants of this gene have been observed and characterized. There are two main splice isoforms denoted LKB1 long (LKB1_L) and LKB1 short (LKB1_S). The short LKB1 variant is predominantly found in testes.

Interactions

STK11 has been shown to interact with:

• CDC37,[19]
• * Fyn[20]
• HSP90AA1[19]
• LYK5,[21][22] and
• SMARCA4.[23]
• ERalpha

Estrogen receptor alpha [24]

References

1. GRCh38: Ensembl release 89: ENSG00000118046 - Ensembl, May 2017
2. GRCm38: Ensembl release 89: ENSMUSG00000003068 - Ensembl, May 2017
3. "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
4. "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
5. Jenne DE, Reimann H, Nezu J, Friedel W, Loff S, Jeschke R, et al. (January 1998). "Peutz-Jeghers syndrome is caused by mutations in a novel serine threonine kinase". Nature Genetics. 18 (1): 38–43. doi:10.1038/ng0198-38. PMID 9425897. S2CID 28986057.
6. McInnes KJ, Brown KA, Hunger NI, Simpson ER (July 2012). "Regulation of LKB1 expression by sex hormones in adipocytes". International Journal of Obesity. 36 (7): 982–5. doi:10.1038/ijo.2011.172. PMID 21876548.
7. Brown KA, McInnes KJ, Takagi K, Ono K, Hunger NI, Wang L, et al. (November 2011). "LKB1 expression is inhibited by estradiol-17β in MCF-7 cells". The Journal of Steroid Biochemistry and Molecular Biology. 127 (3–5): 439–43. doi:10.1016/j.jsbmb.2011.06.005. PMID 21689749. S2CID 25221068.
8. Andrade-Vieira R, Xu Z, Colp P, Marignani PA (2013-02-22). "Loss of LKB1 expression reduces the latency of ErbB2-mediated mammary gland tumorigenesis, promoting changes in metabolic pathways". PLOS ONE. 8 (2): e56567. doi:10.1371/journal.pone.0056567. PMC 3579833. PMID 23451056.
9. Andrade-Vieira R, Goguen D, Bentley HA, Bowen CV, Marignani PA (December 2014). "Pre-clinical study of drug combinations that reduce breast cancer burden due to aberrant mTOR and metabolism promoted by LKB1 loss". Oncotarget. 5 (24): 12738–52. doi:10.18632/oncotarget.2818. PMC 4350354. PMID 25436981.
10. Scott KD, Nath-Sain S, Agnew MD, Marignani PA (June 2007). "LKB1 catalytically deficient mutants enhance cyclin D1 expression". Cancer Research. 67 (12): 5622–7. doi:10.1158/0008-5472.CAN-07-0762. PMID 17575127.
11. Hemminki A, Tomlinson I, Markie D, Järvinen H, Sistonen P, Björkqvist AM, et al. (January 1997). "Localization of a susceptibility locus for Peutz-Jeghers syndrome to 19p using comparative genomic hybridization and targeted linkage analysis". Nature Genetics. 15 (1): 87–90. doi:10.1038/ng0197-87. PMID 8988175. S2CID 8978401.
12. Hemminki A, Markie D, Tomlinson I, Avizienyte E, Roth S, Loukola A, et al. (January 1998). "A serine/threonine kinase gene defective in Peutz-Jeghers syndrome". Nature. 391 (6663): 184–7. Bibcode:1998Natur.391..184H. doi:10.1038/34432. PMID 9428765. S2CID 4400728.
13. Scott R, Crooks R, Meldrum C (October 2008). "Gene symbol: STK11. Disease: Peutz-Jeghers Syndrome". Human Genetics. 124 (3): 300. doi:10.1007/s00439-008-0551-3. PMID 18846624.
14. Sanchez-Cespedes M, Parrella P, Esteller M, Nomoto S, Trink B, Engles JM, et al. (July 2002). "Inactivation of LKB1/STK11 is a common event in adenocarcinomas of the lung". Cancer Research. 62 (13): 3659–62. PMID 12097271.
15. Sanchez-Cespedes M (December 2007). "A role for LKB1 gene in human cancer beyond the Peutz-Jeghers syndrome". Oncogene. 26 (57): 7825–32. doi:10.1038/sj.onc.1210594. PMID 17599048.
16. "Distribution of somatic mutations in STK11". Catalogue of Somatic Mutations in Cancer. Wellcome Trust Genome Campus, Hinxton, Cambridge. Retrieved 2009-11-11.
17. Marignani PA, Scott KD, Bagnulo R, Cannone D, Ferrari E, Stella A, et al. (October 2007). "Novel splice isoforms of STRADalpha differentially affect LKB1 activity, complex assembly and subcellular localization". Cancer Biology & Therapy. 6 (10): 1627–31. doi:10.4161/cbt.6.10.4787. PMID 17921699.
18. PDB: 2WTK​; Zeqiraj E, Filippi BM, Deak M, Alessi DR, van Aalten DM (December 2009). "Structure of the LKB1-STRAD-MO25 complex reveals an allosteric mechanism of kinase activation". Science. 326 (5960): 1707–11. Bibcode:2009Sci...326.1707Z. doi:10.1126/science.1178377. PMC 3518268. PMID 19892943.
19. Boudeau J, Deak M, Lawlor MA, Morrice NA, Alessi DR (March 2003). "Heat-shock protein 90 and Cdc37 interact with LKB1 and regulate its stability". The Biochemical Journal. 370 (Pt 3): 849–57. doi:10.1042/BJ20021813. PMC 1223241. PMID 12489981.
20. Yamada E, Bastie CC (February 2014). "Disruption of Fyn SH3 domain interaction with a proline-rich motif in liver kinase B1 results in activation of AMP-activated protein kinase". PLOS ONE. 9 (2): e89604. Bibcode:2014PLoSO...989604Y. doi:10.1371/journal.pone.0089604. PMC 3934923. PMID 24586906.
21. Boudeau J, Scott JW, Resta N, Deak M, Kieloch A, Komander D, et al. (December 2004). "Analysis of the LKB1-STRAD-MO25 complex". Journal of Cell Science. 117 (Pt 26): 6365–75. doi:10.1242/jcs.01571. PMID 15561763.
22. Baas AF, Boudeau J, Sapkota GP, Smit L, Medema R, Morrice NA, et al. (June 2003). "Activation of the tumour suppressor kinase LKB1 by the STE20-like pseudokinase STRAD". The EMBO Journal. 22 (12): 3062–72. doi:10.1093/emboj/cdg292. PMC 162144. PMID 12805220.
23. Marignani PA, Kanai F, Carpenter CL (August 2001). "LKB1 associates with Brg1 and is necessary for Brg1-induced growth arrest". The Journal of Biological Chemistry. 276 (35): 32415–8. doi:10.1074/jbc.C100207200. PMID 11445556.
24. Nath-Sain S, Marignani PA (June 2009). "LKB1 catalytic activity contributes to estrogen receptor alpha signaling". Molecular Biology of the Cell. 20 (11): 2785–95. doi:10.1091/mbc.e08-11-1138. PMC 2688557. PMID 19369417.

Further reading

• Yoo LI, Chung DC, Yuan J (July 2002). "LKB1--a master tumour suppressor of the small intestine and beyond". Nature Reviews. Cancer. 2 (7): 529–35. doi:10.1038/nrc843. PMID 12094239. S2CID 43512220.
• Baas AF, Smit L, Clevers H (June 2004). "LKB1 tumor suppressor protein: PARtaker in cell polarity". Trends in Cell Biology. 14 (6): 312–9. doi:10.1016/j.tcb.2004.04.001. PMID 15183188.
• Katajisto P, Vallenius T, Vaahtomeri K, Ekman N, Udd L, Tiainen M, Mäkelä TP (January 2007). "The LKB1 tumor suppressor kinase in human disease". Biochimica et Biophysica Acta (BBA) - Reviews on Cancer. 1775 (1): 63–75. doi:10.1016/j.bbcan.2006.08.003. PMID 17010524.
• Bonaldo MF, Lennon G, Soares MB (September 1996). "Normalization and subtraction: two approaches to facilitate gene discovery". Genome Research. 6 (9): 791–806. doi:10.1101/gr.6.9.791. PMID 8889548.
• Bignell GR, Barfoot R, Seal S, Collins N, Warren W, Stratton MR (April 1998). "Low frequency of somatic mutations in the LKB1/Peutz-Jeghers syndrome gene in sporadic breast cancer". Cancer Research. 58 (7): 1384–6. PMID 9537235.
• Nakagawa H, Koyama K, Miyoshi Y, Ando H, Baba S, Watatani M, et al. (August 1998). "Nine novel germline mutations of STK11 in ten families with Peutz-Jeghers syndrome". Human Genetics. 103 (2): 168–72. doi:10.1007/s004390050801. PMID 9760200. S2CID 23986504.
• Mehenni H, Gehrig C, Nezu J, Oku A, Shimane M, Rossier C, et al. (December 1998). "Loss of LKB1 kinase activity in Peutz-Jeghers syndrome, and evidence for allelic and locus heterogeneity". American Journal of Human Genetics. 63 (6): 1641–50. doi:10.1086/302159. PMC 1377635. PMID 9837816.
• Guldberg P, thor Straten P, Ahrenkiel V, Seremet T, Kirkin AF, Zeuthen J (March 1999). "Somatic mutation of the Peutz-Jeghers syndrome gene, LKB1/STK11, in malignant melanoma". Oncogene. 18 (9): 1777–80. doi:10.1038/sj.onc.1202486. PMID 10208439.
• Su GH, Hruban RH, Bansal RK, Bova GS, Tang DJ, Shekher MC, et al. (June 1999). "Germline and somatic mutations of the STK11/LKB1 Peutz-Jeghers gene in pancreatic and biliary cancers". The American Journal of Pathology. 154 (6): 1835–40. doi:10.1016/S0002-9440(10)65440-5. PMC 1866632. PMID 10362809.
• Westerman AM, Entius MM, Boor PP, Koole R, de Baar E, Offerhaus GJ, et al. (1999). "Novel mutations in the LKB1/STK11 gene in Dutch Peutz-Jeghers families". Human Mutation. 13 (6): 476–81. doi:10.1002/(SICI)1098-1004(1999)13:6<476::AID-HUMU7>3.0.CO;2-2. PMID 10408777.
• Scanlan MJ, Gordan JD, Williamson B, Stockert E, Bander NH, Jongeneel V, et al. (November 1999). "Antigens recognized by autologous antibody in patients with renal-cell carcinoma". International Journal of Cancer. 83 (4): 456–64. doi:10.1002/(SICI)1097-0215(19991112)83:4<456::AID-IJC4>3.0.CO;2-5. PMID 10508479.
• Collins SP, Reoma JL, Gamm DM, Uhler MD (February 2000). "LKB1, a novel serine/threonine protein kinase and potential tumour suppressor, is phosphorylated by cAMP-dependent protein kinase (PKA) and prenylated in vivo". The Biochemical Journal. 345 Pt 3 (3): 673–80. doi:10.1042/0264-6021:3450673. PMC 1220803. PMID 10642527.
• Sapkota GP, Kieloch A, Lizcano JM, Lain S, Arthur JS, Williams MR, et al. (June 2001). "Phosphorylation of the protein kinase mutated in Peutz-Jeghers cancer syndrome, LKB1/STK11, at Ser431 by p90(RSK) and cAMP-dependent protein kinase, but not its farnesylation at Cys(433), is essential for LKB1 to suppress cell vrowth". The Journal of Biological Chemistry. 276 (22): 19469–82. doi:10.1074/jbc.M009953200. PMID 11297520.
• Karuman P, Gozani O, Odze RD, Zhou XC, Zhu H, Shaw R, et al. (June 2001). "The Peutz-Jegher gene product LKB1 is a mediator of p53-dependent cell death". Molecular Cell. 7 (6): 1307–19. doi:10.1016/S1097-2765(01)00258-1. PMID 11430832.
• Carretero J, Medina PP, Pio R, Montuenga LM, Sanchez-Cespedes M (May 2004). "Novel and natural knockout lung cancer cell lines for the LKB1/STK11 tumor suppressor gene". Oncogene. 23 (22): 4037–40. doi:10.1038/sj.onc.1207502. PMID 15021901.
• Abed AA, Günther K, Kraus C, Hohenberger W, Ballhausen WG (November 2001). "Mutation screening at the RNA level of the STK11/LKB1 gene in Peutz-Jeghers syndrome reveals complex splicing abnormalities and a novel mRNA isoform (STK11 c.597(insertion mark)598insIVS4)". Human Mutation. 18 (5): 397–410. doi:10.1002/humu.1211. PMID 11668633. S2CID 39255354.
• Sato N, Rosty C, Jansen M, Fukushima N, Ueki T, Yeo CJ, et al. (December 2001). "STK11/LKB1 Peutz-Jeghers gene inactivation in intraductal papillary-mucinous neoplasms of the pancreas". The American Journal of Pathology. 159 (6): 2017–22. doi:10.1016/S0002-9440(10)63053-2. PMC 1850608. PMID 11733352.

External links

• GeneReviews/NCBI/NIH/UW entry on Peutz-Jeghers syndrome
• OMIM entries on Peutz-Jeghers syndrome

This article incorporates text from the United States National Library of Medicine, which is in the public domain.