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
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-α) (1
Mammalian transgelin 2.
Drosophila synchronous flight muscle protein SM20 (1 copy).
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 .
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.
June 2005 / Profile added and text revised.
PROSITE methods (with tools and information) covered by this documentation:
Winder S.J. Walsh M.P.
Calponin: thin filament-linked regulation of smooth muscle contraction.
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