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PsychedeliaDokholyan Laboratory
TargetEnzymes

Dual specificity protein kinase CLK1

Named enzymes, including the metabolising cytochromes and the monoamine oxidases.

Measurements
15
Compounds
1
Binding constants
1
Median pX
7.92

I · Identity

What this target is

Its function as UniProt states it, where in a cell the protein is found, and which cell types and tissues transcribe its gene.

Protein

CLK1_HUMANCLK1Homo sapiens

Dual specificity protein kinase CLK1

Dual specificity kinase acting on both serine/threonine and tyrosine-containing substrates. Phosphorylates serine- and arginine-rich (SR) proteins of the spliceosomal complex and may be a constituent of a network of regulatory mechanisms that enable SR proteins to control RNA splicing. Phosphorylates: SRSF1, SRSF3 and PTPN110480872,19168442. Regulates the alternative splicing of tissue factor (F3) pre-mRNA in endothelial cells19168442

Quoted from UniProt’s FUNCTION annotation for P49759 (reviewed). The superscript numbers are UniProt’s own PubMed citations, kept in the sentence and in order, each linking to the paper it names.

What it acts with

STRING’s highest-confidence human functional partners. The combined score mixes several kinds of evidence, so each channel is shown separately — a partner supported by experiment is a different claim from one supported only by text mining, and for a receptor this is where its coupling appears as evidence rather than as assertion.

PartnerCombinedExperimentDatabaseText mining
CLK40.9590.0000.9000.056
SRSF10.9300.8310.0000.590
DDX230.8590.2060.0000.829
SRSF20.8260.0000.0000.815
CYCS0.8090.0000.0000.809
TRA2A0.7990.7120.0000.207
CLK20.7920.7790.0000.062
NKTR0.7880.0000.0000.762
SRSF30.7580.5400.0000.474
SRPK20.7490.5790.0000.425

Where it sits in the cell

  • Nucleoplasm
  • Nuclear membrane

Human Protein Atlas, by antibody immunofluorescence in cell lines — a different assay from the expression figures below, which are RNA.

UniProt, curated Nucleus

II · Anatomy

Where the gene is transcribed

The same two atlases the compound plates use, asked about this gene alone. Brain on the left, peripheral and autonomic tissues on the right.

Brain

cerebral cortex — 50.9 nTPM, from CLK1cerebellum — 82.9 nTPM, from CLK1hippocampal formation — 86.2 nTPM, from CLK1amygdala — 65.1 nTPM, from CLK1hypothalamus — 71.0 nTPM, from CLK1thalamus — no resolved target expressed herebasal ganglia — 66.4 nTPM, from CLK1medulla oblongata — no resolved target expressed here

basal ganglia: drawn as the caudate nucleus, putamen and globus pallidus.

Measured but not drawn — this anatomogram has no outline for them: retina 123.5, spinal cord 116.1, midbrain 93.6, pituitary gland 85.7.

Body

heart — 82.5 nTPM, from CLK1smooth muscle — 28.7 nTPM, from CLK1lung — 89.3 nTPM, from CLK1liver — 85.3 nTPM, from CLK1kidney — 89.7 nTPM, from CLK1stomach — 52.2 nTPM, from CLK1duodenum — 19.3 nTPM, from CLK1small intestine — 50.6 nTPM, from CLK1colon — 79.7 nTPM, from CLK1adrenal gland — 77.8 nTPM, from CLK1thyroid gland — 93.1 nTPM, from CLK1pancreas — 63.9 nTPM, from CLK1urinary bladder — 90.0 nTPM, from CLK1skeletal muscle — 80.7 nTPM, from CLK1spleen — 113.2 nTPM, from CLK1salivary gland — 67.5 nTPM, from CLK1
0124 nTPM

Square-root ramp · shared scale across both plates

Shading is transcript level — not affinity, and not affinity combined with expression. Outlined but unshaded organs hold none of CLK1 transcript above the atlas’s detection threshold. Anatomy from EMBL-EBI Anatomogram (Apache License 2.0); regions identified by Uberon (uberon.org), CC BY 3.0.

Brain · 10

  • retina123.5 nTPM
  • spinal cord116.1 nTPM
  • midbrain93.6 nTPM
  • hippocampal formation86.2 nTPM
  • pituitary gland85.7 nTPM
  • cerebellum82.9 nTPM
  • hypothalamus71.0 nTPM
  • basal ganglia66.4 nTPM
  • amygdala65.1 nTPM
  • cerebral cortex50.9 nTPM

Peripheral and autonomic · 16

  • spleen113.2 nTPM
  • thyroid gland93.1 nTPM
  • urinary bladder90.0 nTPM
  • kidney89.7 nTPM
  • lung89.3 nTPM
  • liver85.3 nTPM
  • heart muscle82.5 nTPM
  • skeletal muscle80.7 nTPM
  • colon79.7 nTPM
  • adrenal gland77.8 nTPM
  • salivary gland67.5 nTPM
  • pancreas63.9 nTPM
  • stomach 152.2 nTPM
  • small intestine50.6 nTPM
  • smooth muscle28.7 nTPM
  • duodenum19.3 nTPM

Transcript is not protein. These are RNA levels for CLK1, shaded on √nTPM so that a three-order range stays legible — on a linear ramp every region but the strongest would read as blank, which looks like absence rather than less. A region carrying no shading is one the atlas reports no consensus value for, not one where the gene is silent. And a gene being transcribed somewhere is not evidence that any compound reaches it. Human Protein Atlas, RNA expression, nTPM (normalized transcripts per million), consensus tissue dataset.

III · Ranking

Compounds by strongest binding constant

One bar per compound: its strongest Ki or Kd at this target, expressed as pX. Compounds measured here only by a functional assay do not appear — they are in the table below.

  1. 01Harmine7.92

IV · Evidence

Every measurement at this target

Each row links to the ChEMBL assay it came from.

Equilibrium binding constants 1

Ki and Kd — a concentration at equilibrium. Directly comparable across rows at the same target.

TargetClassTypeValue (nM)pXOrganismAssay
Dual specificity protein kinase CLK1EnzymesKd12.117.92Homo sapiensCHEMBL5251384

Functional readouts 9

IC₅₀, EC₅₀, AC₅₀ and potency. Assay-dependent, and not interchangeable with a binding constant.

TargetClassTypeValue (nM)pXOrganismAssay
Dual specificity protein kinase CLK1EnzymesAC5011.607.94Homo sapiensCHEMBL1794519
Dual specificity protein kinase CLK1EnzymesAC5023.007.64Homo sapiensCHEMBL1794519
Dual specificity protein kinase CLK1EnzymesIC5026.007.59Homo sapiensCHEMBL3875857
Dual specificity protein kinase CLK1EnzymesIC5026.007.59Homo sapiensCHEMBL2320044
Dual specificity protein kinase CLK1EnzymesIC5072.007.14Homo sapiensCHEMBL3870427
Dual specificity protein kinase CLK1EnzymesIC5072.007.14Mus musculusCHEMBL2182312
Dual specificity protein kinase CLK1EnzymesIC502206.66Homo sapiensCHEMBL3778247
Dual specificity protein kinase CLK1EnzymesIC50— no normalized value— value does not convert to pXHomo sapiensCHEMBL5251365
Dual specificity protein kinase CLK1EnzymesIC50— no normalized value— value does not convert to pXHomo sapiensCHEMBL5251378

Other measurements 5

Everything else ChEMBL recorded for this compound — percentage inhibition, efficacy, half-life, cytotoxicity. Reported in the assay's own units, which is why no value is converted here.

TargetClassTypeValue (nM)pXOrganismAssay
Dual specificity protein kinase CLK1EnzymesActivity— no normalized value— value does not convert to pXHomo sapiensCHEMBL2186708
Dual specificity protein kinase CLK1EnzymesActivity— no normalized value— value does not convert to pXHomo sapiensCHEMBL4151448
Dual specificity protein kinase CLK1EnzymesActivity— no normalized value— value does not convert to pXHomo sapiensCHEMBL4344392
Dual specificity protein kinase CLK1EnzymesTIME— no normalized value— value does not convert to pXHomo sapiensCHEMBL5251387
Dual specificity protein kinase CLK1EnzymesInhibition— no normalized value— value does not convert to pXHomo sapiensCHEMBL1805398
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