Extended PHD finger found in protein AF-10 and AF-17
The extended plant homeodomain (ePHD) zinc finger is characterized as Cys2HisCys5HisCys2His. This model includes the ePHD finger of AF-10 and AF-17. AF-10, also termed ALL1 (acute lymphoblastic leukaemia)-fused gene from chromosome 10 protein, is a transcription factor encoded by gene AF10, a translocation partner of the MLL (mixed-lineage leukaemia) oncogene in leukaemia. AF-10 has been implicated in the development of leukemia following chromosomal rearrangements between the AF10 gene and one of at least two other genes, MLL and CALM. It plays a key role in the survival of uncommitted hematopoietic cells. Moreover, AF-10 functions as a follistatin-related gene (FLRG)-interacting protein. The interaction with FLRG enhances AF10-dependent transcription. It interacts with the human counterpart of yeast Dot1, hDOT1L, and may act as a bridge for the recruitment of hDOT1L to the genes targeted by MLL-AF10. It also interacts with the synovial sarcoma associated protein SYT protein and may play a role in synovial sarcomas and acute leukemias. AF-17, also termed ALL1-fused gene from chromosome 17 protein, is encoded by gene AF17 that has been identified in hematological malignancies as translocation partners of the mixed lineage leukemia gene MLL. It is a putative transcription factor that may play a role in multiple signaling pathways. It is involved in chromatin-mediated gene regulation mechanisms. It functions as a component of the multi-subunit Dot1 complex (Dotcom) and plays a role in the Wnt/Wingless signaling pathway. It also seems to be a downstream target of the beta-catenin/T-cell factor pathway, and participates in G2-M progression. Moreover, it may function as an important regulator of ENaC-mediated Na+ transport and thus blood pressure. Both AF-10 and AF-17 contain an N-terminal plant homeodomain (PHD) finger followed by this non-canonical ePHD finger. The PHD finger is involved in their homo-oligomerization. In the C-terminal region, they possess a leucine zipper domain and a glutamine-rich region. This family also includes ZFP-1, the Caenorhabditis elegans AF10 homolog. It was originally identified as a factor promoting RNAi interference in C. elegans. It also acts as Dot1-interacting protein that opposes H2B ubiquitination to reduce polymerase II (Pol II) transcription.
Conserved feature residue pattern:C C H C C C C C H C C H
Evidence:
Comment:based on the structure evidence that human Borjeson-Forssman-Lehmann syndrome-associated protein PHF6 (PDB 4NN2) binds three Zn2+ ions through its ePHD finger
Comment:The extended PHD finger is characterized by Cys2HisCys5HisCys2His.
Jiyao W et al.(2023). "The conserved domain database in 2023.",