Four and a half LIM domains protein 1 (FHL1)

Four and a half LIM domains protein 1 (FHL1) is a member of the LIM domain family of proteins, characterized by the presence of zinc-finger motifs responsible for protein-protein interactions[1][2][3]. Located on chromosome Xq26.3, FHL1 is predominantly expressed in skeletal and cardiac muscle, with essential roles in muscle fiber differentiation, maturation, and contractile function[1][2][4]. FHL1 regulates a wide array of cellular processes, including gene transcription, differentiation, apoptosis, and cell cycle control. Alternative splicing generates three isoforms (FHL1A, FHL1B, FHL1C), each with varying LIM domain content and biological roles[1][2][4]. Disease-causing mutations in FHL1 underlie several inherited myopathies and dystrophies[2][3][4]. In cancer biology, FHL1 exhibits complex regulatory roles; it can function either as a tumor suppressor or promote tumor progression depending on cell type and modification status. Regulatory mechanisms include post-transcriptional silencing (e.g., by miR-410 or methylation) and modulation by protein interactions (e.g., SP1, Src, Kindlin-2, estrogen receptors), making it a research focus in oncology and muscle disease biology[1].

Other names

SLIM-1KYO-TFHL1AFHL1BFHL1C

Upregulation or stabilization of FHL1 expression inhibits certain tumor types Drugs (e.g., ATR inhibitors) may act by upregulating deubiquitinating enzymes (e.g., OTUD1) that stabilize FHL1