background:
HEAB is a 425 amino acid nuclear protein that belongs to the Clp1 family. Utilizing magnesium, manganese or nickel as cofactors, HEAB participates in the phosphorylation of the 5'-hydroxyl groups of double- and single- stranded RNA and DNA. HEAB is a member of the tRNA splicing endonuclease complex, in conjunction with TSEN2, TSEN15, TSEN34 and TSEN54, and is also a member of the pre-mRNA cleavage complex II. The gene encoding HEAB maps to human chromosome 11q12.1 and mouse chromosome 2 D; mutations to this gene may lead to a reduced pre-mRNA cleavage activity. HEAB exists as two isoforms due to alternative splicing events.
Function:
Polynucleotide kinase that can phosphorylate the 5'-hydroxyl groups of double-stranded RNA (dsRNA), single-stranded RNA (ssRNA), double stranded DNA (dsDNA) and double-stranded DNA:RNA hybrids. dsRNA is phosphorylated more efficiently than dsDNA, and the RNA component of a DNA:RNA hybrid is phosphorylated more efficiently than the DNA component. Appears to have roles in both tRNA splicing and mRNA 3'-end formation. Component of the tRNA splicing endonuclease complex. Phosphorylates the 5'-terminus of the tRNA 3'-exon during tRNA splicing; this phosphorylation event is a prerequisite for the subsequent ligation of the two exon halves and the production of a mature tRNA. Component of the pre-mRNA cleavage complex II (CF-II), which seems to be required for mRNA 3'-end formation. Also phosphorylates the 5'-terminus of exogenously introduced short interfering RNAs (siRNAs), which is a necessary prerequisite for their incorporation into the RNA-induced silencing complex (RISC). However, endogenous siRNAs and microRNAs (miRNAs) that are produced by the cleavage of dsRNA precursors by DICER1 already contain a 5'-phosphate group, so this protein may be dispensible for normal RNA-mediated gene silencing.
Subunit:
Component of the tRNA splicing endonuclease complex, composed of CLP1, TSEN2, TSEN15, TSEN34 and TSEN54. Component of pre-mRNA cleavage complex II (CF-II). Also associates with numerous components of the pre-mRNA cleavage complex I (CF-I/CFIm), including NUDT21, CPSF2, CPSF3, CPSF6 and CPSF7. Interacts with CSTF2 and SYMPK.
Subcellular Location:
Nucleus.
Similarity:
Belongs to the Clp1 family. Clp1 subfamily.
Database links:
UniProtKB/Swiss-Prot: Q92989.1
Important Note:
This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications.
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