PROSITE documentation PDOC51266
Zinc finger CHY-type and CTCHY-type profiles


Pirh2 is an eukaryotic ubiquitin protein ligase, which has been shown to promote p53 degradation in mammals. Pirh2 physically interacts with p53 and promotes ubiquitination of p53 independently of MDM2. Like MDM2, Pirh2 is thought to participate in an autoregulatory feedback loop that controls p53 function. Pirh2 proteins contain three distinct zinc fingers, the CHY-type, the CTCHY-type which is C-terminal to the CHY-type zinc finger and a RING finger (see <PDOC00449>). The CHY-type zinc finger has no known functions but the region encompassing the CTCHY-type zinc finger is required for binding to p53 in mammals [1].

The CTCHY-type zinc finger is only found in pirh2 proteins, whereas the CHY-type zinc finger is also found in the following proteins:

  • Yeast helper of Tim protein 13. Hot13 may have a role in the assembly and recycling of the small Tims, a complex of the mitochondrial intermembrane space that participates in the TIM22 import pathway for assembly of the inner membrane [2].
  • Several plant hypothetical proteins that also contain hemerythrin cation binding domains.
  • Several protozoan hypothetical proteins that also contain a Myb domain.

The solution structure of the CHY-type and the CTCHY-type zinc fingers has been solved (see <PDB:2DKT>). Each conserved region binds 3 zinc atoms as shown in the following schematic representations:

The CHY-type zinc finger:

                      ||         |     |
         | |                 |  |                  |  |         |  |
         +-+-----------------+--+                  +--+---------+--+

The CTCHY-type zinc finger:

                             |  |            |      |
              |  |          |      |          |  |           | |
              +--+----------+------+          +--+-----------+-+
'C': conserved cysteine involved in the binding of one zinc atom.
'H': conserved histidine involved in the binding of one zinc atom.

The first profile covers the entire CHY-type zinc finger and the second one the whole CTCHY-type zinc finger.

Last update:

November 2006 / First entry.


Technical section

PROSITE methods (with tools and information) covered by this documentation:

ZF_CHY, PS51266; Zinc finger CHY-type profile  (MATRIX)

ZF_CTCHY, PS51270; Zinc finger CTCHY-type profile  (MATRIX)


1AuthorsLeng R.P. Lin Y. Ma W. Wu H. Lemmers B. Chung S. Parant J.M. Lozano G. Hakem R. Benchimol S.
TitlePirh2, a p53-induced ubiquitin-protein ligase, promotes p53 degradation.
SourceCell 112:779-791(2003).
PubMed ID12654245

2AuthorsCurran S.P. Leuenberger D. Leverich E.P. Hwang D.K. Beverly K.N. Koehler C.M.
TitleThe role of Hot13p and redox chemistry in the mitochondrial TIM22 import pathway.
SourceJ. Biol. Chem. 279:43744-43751(2004).
PubMed ID15294910

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