{PDOC00547}
{PS00629; IMP_1}
{PS00630; IMP_2}
{BEGIN}
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* Inositol monophosphatase family signatures *
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It has been shown [1] that several proteins share two sequence motifs.  Two of
these  proteins  are  enzymes  of  the  inositol  phosphate  second  messenger
signalling pathway:

 - Vertebrate,    plants    and    microbial    myo-inositol   monophosphatase
   (EC 3.1.3.25).
 - Vertebrate inositol polyphosphate 1-phosphatase (EC 3.1.3.57).

The function of the other proteins is not yet clear:

 - Bacterial  protein  cysQ.  CysQ  could  help  to  control  the pool of PAPS
   (3'-phosphoadenoside 5'-phosphosulfate), or be useful in sulfite synthesis.
 - Neurospora crassa protein Qa-X. Probably involved in quinate metabolism.
 - Emericella nidulans protein qutG. Probably involved in quinate metabolism.
 - Yeast  protein  HAL2/MET22  [2]  involved  in  salt  tolerance  as  well as
   methionine biosynthesis.
 - Yeast hypothetical hypothetical protein YHR046c.
 - Caenorhabditis elegans hypothetical protein F13G3.5.

It is suggested [1] that these proteins may  act by enhancing the synthesis or
degradation of phosphorylated messenger molecules. From the X-ray structure of
human  inositol monophosphatase [3], it  seems  that  some  of  the  conserved
residues are involved in binding a metal ion and/or the phosphate group of the
substrate.

-Consensus pattern: [FWV]-x(0,1)-[LIVM]-D-P-[LIVM]-D-[SG]-[ST]-x(2)-[FYA]-
                    x(0,1)-[HKRNSTY]
                    [The first D and the T bind a metal ion]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Consensus pattern: [WYV]-D-x-[AC]-[GSA]-[GSAPV]-x-[LIVFACP]-[LIVM]-[LIVAC]-
                    x(3)-[GH]-[GA]
-Sequences known to belong to this class detected by the pattern: ALL,  except
 for cysQ from Mycobacterium leprae.
-Other sequence(s) detected in Swiss-Prot: 1.

-Last update: April 2006 / Pattern revised.

[ 1] Neuwald A.F., York J.D., Majerus P.W.
     "Diverse proteins homologous to inositol monophosphatase."
     FEBS Lett. 294:16-18(1991).
     PubMed=1660408
[ 2] Glaeser H.-U., Thomas D., Gaxiola R., Montrichard F., Surdin-Kerjan Y.,
     Serrano R.
     EMBO J. 12:3105-3110(1993).
[ 3] Bone R., Springer J.P., Atack J.R.
     "Structure of inositol monophosphatase, the putative target of lithium
     therapy."
     Proc. Natl. Acad. Sci. U.S.A. 89:10031-10035(1992).
     PubMed=1332026

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