{PDOC00808}
{PS01052; CALPONIN_1}
{PS51122; CALPONIN_2}
{BEGIN}
**********************************************
* Calponin-like repeat signature and profile *
**********************************************

Calponin [1,2] is a thin filament-associated protein that is implicated in the
regulation and  modulation  of  smooth  muscle  contraction.  It is capable of
binding to  actin,  calmodulin, troponin C and tropomyosin. The interaction of
calponin with  actin  inhibits the actomyosin MgATPase activity. Calponin is a
basic protein  of  approximately 34 Kd.  Multiple isoforms are found in smooth
muscles.

Calponin contains  three  repeats  of a well conserved motif of about 26 amino
acids. Such  a  domain  is  also  found  in  a  number of other proteins whose
physiological role is not yet established:

 - Vertebrate  transgelin  (also known as smooth muscle protein SM22-alpha) (1
   copy).
 - Mammalian transgelin 2.
 - Drosophila synchronous flight muscle protein SM20 (1 copy).
 - Rat neuronal protein NP25 [3] (1 copy).
 - Caenorhabditis elegans protein unc-87 [4] (5 copies).
 - An Onchocerca volvulus antigen [5] (5 copies).

Most of  these proteins also contain a N-terminal CH domain (see <PDOC50021>).
The calponin-like  repeat is a short actin-binding module. Actin-binding sites
formed by  either  CH  domains  or  calponin-like repeats occupy non-competing
binding sites along the actin filament [6].

We developed  both  a  pattern and a profile for the calponin-like repeat. The
signature pattern  corresponds  to  the first 20 residues, whereas the profile
covers the entire calponin-like repeat.

-Consensus pattern: [LIVM]-x-[LS]-Q-[MASY]-G-[STY]-[NT]-[KRQ]-x(2)-[STN]-Q-x-
                    G-x(3,4)-G
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Last update: June 2005 / Profile added and text revised.

[ 1] Winder S.J., Walsh M.P.
     "Calponin: thin filament-linked regulation of smooth muscle
     contraction."
     Cell. Signal. 5:677-686(1993).
     PubMed=8130072
[ 2] Applegate D.E., Feng W., Green R.S., Taubman M.B.
     "Cloning and expression of a novel acidic calponin isoform from rat
     aortic vascular smooth muscle."
     J. Biol. Chem. 269:10683-10690(1994).
     PubMed=8144658
[ 3] Ren W.-Z., Ng G.Y.K., Wang R.-X., Wu P.H., O'Dowd B.F., Osmond D.H.,
     George S.R., Liew C.-C.
     "The identification of NP25: a novel protein that is differentially
     expressed by neuronal subpopulations."
     Brain Res. Mol. Brain Res. 22:173-185(1994).
     PubMed=8015377
[ 4] Goetinck S.D., Waterston R.H.
     "The Caenorhabditis elegans muscle-affecting gene unc-87 encodes a
     novel thin filament-associated protein."
     J. Cell Biol. 127:79-93(1994).
     PubMed=7929573
[ 5] Irvine M., Huima T., Prince A.M., Lustigman S.
     "Identification and characterization of an Onchocerca volvulus cDNA
     clone encoding a highly immunogenic calponin-like protein."
     Mol. Biochem. Parasitol. 65:135-146(1994).
     PubMed=7935620
[ 6] Lener T., Burgstaller G., Gimona M.
     "The role of calponin in the gene profile of metastatic cells:
     inhibition of metastatic cell motility by multiple calponin repeats."
     FEBS Lett. 556:221-226(2004).
     PubMed=14706854

--------------------------------------------------------------------------------
PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and
distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives
(CC BY-NC-ND 4.0) License, see https://prosite.expasy.org/prosite_license.html
--------------------------------------------------------------------------------

{END}