MYLK3: Myosin Light Chain Kinase 3
A cardiac-specific kinase regulating myocardial contractility and sarcomere organization
Gene Information Card
| Symbol | MYLK3 |
|---|---|
| Full Name | myosin light chain kinase 3 |
| Gene Type | protein-coding |
| Chromosomal Location | 16q11.2 |
| NCBI Gene ID | 91807 ncbi.nlm.nih.gov/gene/91807 |
| Ensembl ID | ENSG00000103044 |
| UniProt ID | Q32MK0 |
| OMIM ID | 613543 |
| HGNC ID | 29824 |
| Aliases | MLCK3, caMLCK, MLCK, cardiac MLCK |
Description
MYLK3 encodes a cardiac-specific myosin light chain kinase that phosphorylates the regulatory light chain of myosin (MYL2) in heart muscle. This phosphorylation is essential for sarcomere assembly, myofibril organization, and normal cardiac contractility. MYLK3 is predominantly expressed in the heart and plays a critical role in cardiomyocyte differentiation and function.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Dilated cardiomyopathy (DCM) | Loss-of-function mutations impair MYL2 phosphorylation, disrupting sarcomere assembly and contractile force generation. | ClinVar, OMIM |
| Hypertrophic cardiomyopathy (HCM) | Missense variants may alter kinase activity or substrate binding, leading to aberrant myosin regulation and hypertrophy. | ClinVar, OMIM |
| Left ventricular noncompaction (LVNC) | MYLK3 mutations associated with reduced kinase activity impair myocardial compaction during development. | ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Heart | 58.2 | High |
| Skeletal muscle | 2.1 | Low |
| Brain | 0.5 | Not detected |
| Liver | 0.3 | Not detected |
| Lung | 0.4 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Cardiomyocytes (iPSC-derived) | 62.8 | High expression; essential for sarcomere formation |
| HeLa | 0.2 | Not detected |
| HEK293 | 0.1 | Not detected |
| HepG2 | 0.3 | Not detected |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.172C>T (p.Arg58Trp) | Missense | <0.01% | Reduced kinase activity; associated with DCM |
| c.1045G>A (p.Glu349Lys) | Missense | <0.01% | Impaired MYL2 phosphorylation; HCM risk |
| c.1234del (p.Leu412fs) | Frameshift | <0.01% | Loss of function; truncation; DCM |
Mutation functional classification
Loss of Function (LOF)
Frameshift and nonsense mutations (e.g., p.Leu412fs) lead to truncated, non-functional kinase, reducing MYL2 phosphorylation and sarcomere integrity.
Gain of Function (GOF)
No confirmed gain-of-function mutations reported in MYLK3.
Dominant Negative (DN)
Missense variants (e.g., p.Arg58Trp) may act dominant-negative by dimerizing with wild-type kinase and impairing overall activity.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Cardiac muscle contraction (KEGG: hsa04260)
• cGMP-PKG signaling pathway (KEGG: hsa04022)
• Regulation of actin cytoskeleton (KEGG: hsa04810)
Protein Summary
MYLK3 (cardiac myosin light chain kinase) is a 100 kDa serine/threonine kinase specifically expressed in cardiac muscle. It phosphorylates the regulatory light chain of myosin (MYL2) at Ser15, a key step for myosin motor function and sarcomere assembly. The protein contains an N-terminal kinase domain, a calmodulin-binding region, and a C-terminal domain involved in localization to the sarcomere. MYLK3 activity is calcium/calmodulin-dependent and essential for maintaining cardiac contractility. Loss-of-function mutations cause dilated cardiomyopathy, while missense variants are linked to hypertrophic cardiomyopathy and left ventricular noncompaction.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| MYLK3 Knockout HEK293 Cell Line | EDJ-KQ853 | Human | 91807 | Details Get a Quote |
| MYLK3 Knockout HeLa Cell Line | EDJ-KQ20983 | Human | 91807 | Details Get a Quote |
| MYLK3 Knockout A-549 Cell Line | EDJ-KQ66309 | Human | 91807 | Details Get a Quote |
| MYLK3 Knockout HCT 116 Cell Line | EDJ-KQ74732 | Human | 91807 | Details Get a Quote |
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