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Details on Person UniProt:Q15746-1 MYLK

Class:IdReferenceIsoform:58173
_chainChangeLogchain:1-1914 added on Fri February 6 2015;chain:1-1910 added on Fri February 6 2015;initiator methionine: for 58173 added on Sun February 16 2020;initiator methionine: for 58173 added on Sun February 16 2020;initiator methionine: for 58173 removed on Fri Aug 15 2025;initiator methionine: for 58173 removed on Fri Aug 15 2025;initiator methionine:1 for 58173 added on Fri Aug 15 2025;initiator methionine:1 for 58173 added on Fri Aug 15 2025
_displayNameUniProt:Q15746-1 MYLK
_timestamp2025-08-15 21:54:43
chainchain:1-1914
chain:1-1910
initiator methionine:1
initiator methionine:1
checksum2D094E161CE2D4BA
commentFUNCTION Calcium/calmodulin-dependent myosin light chain kinase implicated in smooth muscle contraction via phosphorylation of myosin light chains (MLC). Also regulates actin-myosin interaction through a non-kinase activity. Phosphorylates PTK2B/PYK2 and myosin light-chains. Involved in the inflammatory response (e.g. apoptosis, vascular permeability, leukocyte diapedesis), cell motility and morphology, airway hyperreactivity and other activities relevant to asthma. Required for tonic airway smooth muscle contraction that is necessary for physiological and asthmatic airway resistance. Necessary for gastrointestinal motility. Implicated in the regulation of endothelial as well as vascular permeability, probably via the regulation of cytoskeletal rearrangements. In the nervous system it has been shown to control the growth initiation of astrocytic processes in culture and to participate in transmitter release at synapses formed between cultured sympathetic ganglion cells. Critical participant in signaling sequences that result in fibroblast apoptosis. Plays a role in the regulation of epithelial cell survival. Required for epithelial wound healing, especially during actomyosin ring contraction during purse-string wound closure. Mediates RhoA-dependent membrane blebbing. Triggers TRPC5 channel activity in a calcium-dependent signaling, by inducing its subcellular localization at the plasma membrane. Promotes cell migration (including tumor cells) and tumor metastasis. PTK2B/PYK2 activation by phosphorylation mediates ITGB2 activation and is thus essential to trigger neutrophil transmigration during acute lung injury (ALI). May regulate optic nerve head astrocyte migration. Probably involved in mitotic cytoskeletal regulation. Regulates tight junction probably by modulating ZO-1 exchange in the perijunctional actomyosin ring. Mediates burn-induced microvascular barrier injury; triggers endothelial contraction in the development of microvascular hyperpermeability by phosphorylating MLC. Essential for intestinal barrier dysfunction. Mediates Giardia spp.-mediated reduced epithelial barrier function during giardiasis intestinal infection via reorganization of cytoskeletal F-actin and tight junctional ZO-1. Necessary for hypotonicity-induced Ca(2+) entry and subsequent activation of volume-sensitive organic osmolyte/anion channels (VSOAC) in cervical cancer cells. Responsible for high proliferative ability of breast cancer cells through anti-apoptosis.CATALYTIC ACTIVITY L-seryl-[myosin light chain] + ATP = O-phospho-L-seryl-[myosin light chain] + ADP + H(+)CATALYTIC ACTIVITY L-threonyl-[myosin light chain] + ATP = O-phospho-L-threonyl-[myosin light chain] + ADP + H(+)COFACTOR Isoform 1 is activated by phosphorylation on Tyr-464 and Tyr-471. Isoforms which lack these tyrosine residues are not regulated in this way. All catalytically active isoforms require binding to calcium and calmodulin for activation. Repressed by organometallic pyridylnaphthalimide complexes, wortmannin, ML-7 (a synthetic naphthalenesulphonyl derivative that inhibits the binding of ATP to MLCK) and ML-9.BIOPHYSICOCHEMICAL PROPERTIES All isoforms including Telokin bind calmodulin. Interacts with SVIL (By similarity). Interacts with CTTN; this interaction is reduced during thrombin-induced endothelial cell (EC) contraction but is promoted by the barrier-protective agonist sphingosine 1-phosphate (S1P) within lamellipodia. A complex made of ABL1, CTTN and MYLK regulates cortical actin-based cytoskeletal rearrangement critical to sphingosine 1-phosphate (S1P)-mediated endothelial cell (EC) barrier enhancement. Binds to NAA10/ARD1 and PTK2B/PYK2.INTERACTION Localized to stress fibers during interphase and to the cleavage furrow during mitosis.ALTERNATIVE PRODUCTS Smooth muscle and non-muscle isozymes are expressed in a wide variety of adult and fetal tissues and in cultured endothelium with qualitative expression appearing to be neither tissue- nor development-specific. Non-muscle isoform 2 is the dominant splice variant expressed in various tissues. Telokin has been found in a wide variety of adult and fetal tissues. Accumulates in well differentiated enterocytes of the intestinal epithelium in response to tumor necrosis factor (TNF).INDUCTION Accumulates in individuals with asthma (at protein levels). Induced by tumor necrosis factor (TNF). Repressed by androgens (e.g. R1881).PTM Can probably be down-regulated by phosphorylation. Tyrosine phosphorylation by ABL1 increases kinase activity, reverses MLCK-mediated inhibition of Arp2/3-mediated actin polymerization, and enhances CTTN-binding. Phosphorylation by SRC at Tyr-464 and Tyr-471 promotes CTTN binding.PTM The C-terminus is deglutamylated by AGTPBP1/CCP1, AGBL1/CCP4 and AGBL4/CCP6, leading to the formation of Myosin light chain kinase, smooth muscle, deglutamylated form. The consequences of C-terminal deglutamylation are unknown (By similarity).PTM Acetylated at Lys-608 by NAA10/ARD1 via a calcium-dependent signaling; this acetylation represses kinase activity and reduces tumor cell migration.DISEASE The disease is caused by variants affecting the gene represented in this entry.DISEASE The disease is caused by variants affecting the gene represented in this entry.MISCELLANEOUS In asthmatic patients, overexpression promotes actin filament propulsion, thus contributing to airway hyperresponsiveness. Some MYLK variants may contribute to acute lung injury (ALI) susceptibility. Potential therapeutic target in the treatment of burn edema.MISCELLANEOUS Transcribed from an alternative promoter resulting in the usage of Met-923 as initiator codon.MISCELLANEOUS Transcribed from an alternative promoter resulting in the usage of Met-1761 as initiator codon. Has no catalytic activity. Initiator Met is removed.MISCELLANEOUS Transcribed from an alternative promoter resulting in the usage of Met-1761 as initiator codon. Initiator Met is removed.MISCELLANEOUS Transcribed from an alternative promoter resulting in the usage of Met-923 as initiator codon.SIMILARITY Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family.SEQUENCE CAUTION Myosin light-chain kinase entry
descriptionrecommendedName: fullName evidence="45"Myosin light chain kinase, smooth muscle shortName: MLCK shortName: smMLCK ecNumber evidence="9"2.7.11.18 alternativeName: Kinase-related protein shortName: KRP alternativeName: Telokin component recommendedName: Myosin light chain kinase, smooth muscle, deglutamylated form /component
geneNameMYLK
MLCK
MLCK1
MYLK1
identifierQ15746
isoformParent
isSequenceChangedFALSE
keyword3D-structure
Acetylation
Actin-binding
Alternative promoter usage
Alternative splicing
Aortic aneurysm
ATP-binding
Calcium
Calmodulin-binding
Cell projection
Cytoplasm
Cytoskeleton
Direct protein sequencing
Disease variant
Disulfide bond
Immunoglobulin domain
Kinase
Magnesium
Metal-binding
Nucleotide-binding
Phosphoprotein
Proteomics identification
Reference proteome
Repeat
Serine/threonine-protein kinase
Transferase
modified[InstanceEdit:9836292] Weiser, Joel, 2023-05-25
[InstanceEdit:9852000] Weiser, Joel, 2023-11-03
[InstanceEdit:9926675] Weiser, Joel, 2024-11-03
[InstanceEdit:9939033] Weiser, Joel, 2025-02-21
[InstanceEdit:9963647] Weiser, Joel, 2025-08-15
nameMYLK
referenceDatabase[ReferenceDatabase:2] UniProt
referenceGene[ReferenceDNASequence:8961102] ENSEMBL:ENSG00000065534 MYLK [Homo sapiens]
secondaryIdentifierMYLK_HUMAN
B4DUE3
D3DN97
O95796
O95797
O95798
O95799
Q14844
Q16794
Q17S15
Q3ZCP9
Q5MY99
Q5MYA0
Q6P2N0
Q7Z4J0
Q9C0L5
Q9UBG5
Q9UBY6
Q9UIT9
sequenceLength1914
species[Species:48887] Homo sapiens
variantIdentifierQ15746-1
(referenceEntity)[EntityWithAccessionedSequence:375980] MYLK-1 [plasma membrane] [Homo sapiens]
[EntityWithAccessionedSequence:375982] p-S439,S991-MYLK-1 [plasma membrane] [Homo sapiens]
(referenceSequence)[ModifiedResidue:375984] O-phospho-L-serine at 439
[ModifiedResidue:375985] O-phospho-L-serine at 991
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No pathways have been reviewed or authored by UniProt:Q15746-1 MYLK (58173)