MYCL

MYCL, also known as L-Myc, is a gene in humans that encodes a member of the Myc family of transcription factors. Like other Myc proteins, L-Myc is a basic helix-loop-helix leucine zipper (bHLHZ) factor that dimerizes with MAX to regulate gene expression. The L-Myc/MAX complex binds to E-box sequences in promoters and enhancers, influencing transcription programs that control cell growth, metabolism, ribosome biogenesis, differentiation, and apoptosis.

In development, MYCL is expressed in restricted patterns and contributes to the proliferation and maturation of specific tissues, including parts of the lung and nervous system. Its activity is tightly regulated at multiple levels, including transcription, translation, and protein stability, and it interacts with other transcriptional regulators within the Myc network.

In humans, MYCL can act as an oncogene when amplified or overexpressed. Amplification or elevated expression of MYCL has been reported in a subset of cancers, with particular study in small cell lung carcinoma. Experimental models show that L-Myc can cooperate with other oncogenic events to promote tumorigenesis, highlighting the role of the Myc network in cancer biology.

Because of its central role in controlling cell growth and metabolism, MYCL is a focus of cancer biology and systems-level analyses of Myc-driven transcriptional programs. Therapeutic strategies aimed at disrupting Myc:MAX dimerization or downstream effectors are explored broadly, though no MYCL-specific approved therapies exist.