lethal[3]malignant brain tumor-like protein; L[3]mbt-like; L[3]mbt protein homolog; H-l[3]mbt protein; H-L[3]MBT (L3MBTL1, L3MBTL, KIAA0681, L3MBT)

Function

• polycomb group protein (PcG)
• ETV6-mediated repression
• role in cell proliferation, mitosis
• overexpression induces multinucleated cells
• interacts with ETV6
• ubiquitinated (VCP/p97-dependent) following DNA damage, leading to its removal from DNA damage sites, promoting accessibility of H4K20me2 mark for DNA repair protein TP53BP1, which is then recruited to DNA damage sites
• interacts with RB1/RB (when monomethylated at 'Lys-860')
• interacts with p53/TP53 (when monomethylated at 'Lys-382')
• interacts with CBX3, ETV6, SETD8 & VCP/p97

Structure

• homodimer
• the MBT repeat 2 specifically recognizes & binds monomethylated & dimethylated proteins
• in contrast, it does not bind trimethylated proteins
• the MBT repeat 1 does not bind methylated peptides but inserts a proline ring in a Pro-Ser-Ser/Thr sequence context
• contains 1 C2HC-type Zn+2 finger
• contains 3 MBT repeats
• contains 1 SAM (sterile alpha motif) domain

Compartment

• nucleus ,excluded from the nucleolus
• does NOT colocalize with the PcG protein BMI1
• in interphase cells, scattered throughout nucleoplasm
• in mitotic cells, associates with condensed chromosomes from prophase to telophase

Alternative splicing

named isoforms=5

Expression

• widely expressed

Pathology

• expression diminished in colorectal cancer cell line & promyelocytic leukemia cell

Genetics

• the L3MBTL1 locus is imprinted
• paternal inherited gene is expressed, while the maternal inherited gene is silenced

More general terms

• zinc finger protein
• nuclear protein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=26013
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:26013
• OMIM: https://mirror.omim.org/entry/608802
• UniProt: http://www.uniprot.org/uniprot/Q9Y468.html