Recombinant Human E3 ubiquitin-protein ligase Hakai (CBLL1) Fragment (residues 103-192) is a high-purity, stable protein fragment designed for structural and biochemical studies. This 90-amino acid fragment, derived from the Hakai protein, offers a soluble and well-behaved unit ideal for investigating the ubiquitination mechanisms and molecular interactions of this key regulatory enzyme.

E3 ubiquitin-protein ligase Hakai, encoded by the CBLL1 gene in humans, functions as a RING-type E3 ubiquitin transferase that mediates ubiquitination of tyrosine-phosphorylated Src substrates including CDH1, CTTN, and DOK1. It targets CDH1 for endocytosis and degradation, playing crucial roles in protein regulation and turnover. Additionally, Hakai serves as an associated component of the WMM complex, which mediates N6-methyladenosine (m6A) methylation of RNAs - a modification important for mRNA splicing efficiency and RNA processing. The protein exhibits dual localization, primarily in nuclear speckles and nucleoplasm with some cytoplasmic presence, and requires ZC3H13 for proper nuclear anchoring of MACOM subcomplex components. This fragment represents a stable, soluble region selected for experimental utility while maintaining relevance to the full-length protein's functional context.