Protein fem-1 homolog B (FEM1B)

Protein fem-1 homolog B (FEM1B) is an ankyrin repeat-containing protein that acts as the substrate recognition component of the CUL2-RING E3 ubiquitin-protein ligase complex within the DesCEND (destruction via C-end degrons) pathway[1][5]. FEM1B selectively binds C-terminal degron motifs on target proteins, mediating their ubiquitination and proteasomal degradation, which is critical for protein quality control in the cell[1][5]. Functionally, FEM1B regulates the reductive stress response—the process by which cells recalibrate reactive oxygen species levels, particularly by targeting the mitochondrial protein FNIP1 for degradation through a zinc-dependent mechanism[2][6]. It also participates in apoptosis as a death receptor-associated protein and is involved in the regulation of glucose homeostasis in pancreatic islet cells and checkpoint signaling during DNA replication stress[1][4][5]. Dysregulation of FEM1B and the associated CRL2(FEM1B) complex is implicated in cancer, diabetes, cardiomyopathy, and Type C thymoma[1][2]. Despite its essential roles, no drugs targeting FEM1B are currently documented, nor is it established as a clinical biomarker.

Other names

FEM1BF1AAKIAA0396Fem-1-like death receptor-binding protein alphaFem-1-like in apoptotic pathway protein alphaF1A-alphaFEM1-betaNEDBESprotein fem-1 homolog BFEM-1-like death receptor binding proteinfem-1-like death receptor-binding protein alphafem-1-like in apoptotic pathway protein alphaF1A-ALPHA