MYL9
Overview
MYL9 (Myosin Light Chain 9) encodes a regulatory myosin light chain involved in smooth muscle contraction and cell motility. In normal skin biology, MYL9 is identified as a transcriptomic marker of the LowMut (neural-crest lineage) melanocyte subpopulation, which carries far fewer UV-attributable somatic mutations than the HighMut (pigmentation-active) counterpart.
Alterations observed in the corpus
- MYL9 is a transcriptomic LowMut marker in normal human skin melanocytes; expressed in the low-mutation-burden subpopulation that clusters with Belote et al. “MSC” and WIMMS “AXL/Neuronal/Invasive” melanocyte states. Co-expressed with VCAN, FBN1, PALLD, ITM2A, TAGLN, MYLK, SGCE, HACD1, SEMA3C, TCF4, DAAM2, RGMB, and NTNG1. PMID:39975212
Cancer types (linked)
- SKCM: The atlas was generated from non-lesional skin adjacent to a melanoma patient; LowMut-cell identity (marked by MYL9 among others) may be relevant to melanoma cell-of-origin hypotheses, though no somatic driver role for MYL9 is claimed. PMID:39975212
Co-occurrence and mutual exclusivity
Therapeutic relevance
- No direct therapeutic link reported. The LowMut melanocyte subpopulation is proposed as a UV-protected reservoir capable of repigmentation, with speculative relevance to melanoma interception by replacing heavily mutated cells. PMID:39975212
Open questions
- Whether LowMut/MYL9-high melanocytes represent a genuinely distinct cell lineage versus a transient state, and whether they serve as a cell-of-origin for a melanoma subtype, is not resolved. PMID:39975212
Sources
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