Interaction of calponin with actin and its functional implications

Kolakowski, Janusz; Makuch, Robert W.; Stȩpkowski, Dariusz; Da̧browska, Renata

doi:10.1042/bj3060199

Cited by 51 publications

(61 citation statements)

References 39 publications

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“…At intermediate ionic strength (10 mM Tris/acetate, pH 8.3, 30-50 mM NaC1) the apparent dissociation constant increased up to 11-15 ~tM and the stoichiometry became equal to 1 mol calponin per 4-6 mol desmin. Thus, the stoichiometry of the calponin~tesmin complex is similar to that of calponin-actin (1 calponin/2~, mol target protein) and affinity of calponin to desmin is 10-100 times lower than that to actin [2,9,24,25]. Nevertheless, taking into account rather high content of both calponin and desmin in smooth muscle (= 130-150 pM for both proteins) [22,24], desmin-calponin interaction may be of physiological significance.…”

Section: Resultsmentioning

confidence: 96%

“…On one hand, calponin has been deduced to play a role in the regulation of smooth-muscle contraction [2,5,7]. On the other hand, the low efficiency of calponin in inhibition of actomyosin ATPase [8,9] and its wide distribution in nonmuscle tissues (such as brain, fibroblasts and platelets) [2,4,10] may indicate that calponin is not only involved in regulation of the actomyosin system but also has other functions.…”

Section: Introductionmentioning

confidence: 99%

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Interaction of smooth muscle calponin and desmin

Wang

Gusev

1996

FEBS Letters

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Interaction of smooth-muscle calponin and desmin was analyzed by means of ultracentrifugation, fluorescent spectroscopy and affinity chromatography. At low and intermediate ionic strength (30-50 mM NaCI) eaiponin is cosedimented with desmin with an apparent dissociation constant 3-15 IxM and stoichiometry of 1 calponin/4-6 desmin. Calmodulin decreases the quantity of calponin bound to desmin. Increase of ionic strength up to 150 mM weakens calponin-desmin interaction, but even at this ionic strength part of calponin remains bound to desmin. Calponin increases the rate and extent of fluorescence quenching induced by polymerization of 5-iodoacetamidofluorescein-labeled desmin. Affmity chromatography data indicate that desmin-binding sites are located in the N-terminal 22 kDa fragment of calponin. Since calponin interacts with desmin with an affinity comparable with that of, e.g., tropomyosin and myosin we suppose that calponin-desmin interaction may be important for cytoskeleton organization.

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Section: Resultsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Interaction of smooth muscle calponin and desmin

Wang

Gusev

1996

FEBS Letters

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“…It has been reported that CaP at high concentrations can induce bundles of smooth muscle F-actin (23). When smooth or skeletal muscle F-actin were incubated together with UNC-87 and centrifuged for 20 min at 18,000 ϫ g, actin and UNC-87 were found together in the low speed pellet, indicating the induction of actin bundles by UNC-87 (Fig.…”

Section: Expression and Purification Of Recombinant Unc-87-thementioning

confidence: 91%

UNC-87 Is an Actin-bundling Protein

Kranewitter

Ylänne

Gimona

2001

Journal of Biological Chemistry

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The Caenorhabditis elegans unc-87 gene product is essential for the maintenance of the nematode body wall muscle where it is found colocalized with actin in the I band. The molecular domain structure of the protein reveals similarity to the C-terminal repeat region of the smooth muscle actin-binding protein calponin. In this study we investigated the in vitro function of UNC-87 using both the full-length recombinant molecule and several truncated mutants. According to analytical ultracentrifugation UNC-87 occurs as a monomer in solution. UNC-87 cosedimented with both smooth and skeletal muscle F-actin, but not with monomeric G-actin, and exhibited potent actin filament bundling activity. Actin binding was independent of the presence of tropomyosin and the actin cross-linking proteins filamin and ␣-actinin. Consistent with its actin bundling activity in vitro, UNC-87 tagged with green fluorescent protein associated with and promoted the formation of actin stress fiber bundles in living cells. These data identify UNC-87 as an actin-bundling protein and highlight the calponin-like repeats as a novel actin-binding module.The interaction of actin and myosin to produce force is an essential prerequisite for a variety of cellular processes including muscle contraction (1), cell motility, and anchorage (2). The organization of contractile and motile systems based on actin relies on a large family of actin-associated proteins that regulate and define the assembly of actin into filaments and then into filament arrays (3, 4). To date, more than 60 different proteins directly interacting with actin have been identified, but the majority of F-actin-binding proteins populate partially overlapping regions on the filament (5, 6). Despite the large number of actin-binding proteins, functional diversity is reflected by a limited number of basic structural modules (7). Most actin cross-linking proteins exhibit two independent actin-binding domains, each individual actin-binding domain commonly composed of a tandem arrangement of the calponin homology domain module (8) and other modular elements defining the distance between and the relative orientation of the two actin-binding domains, often involving parallel or antiparallel dimerization (7).We have shown recently that a unique sequence motif found in the C-terminal third of the calponin (CaP) 1 molecule and other members of the CaP family of actin-associated proteins (9), namely a 23-amino acid residue repeat, which we will refer to from now on as the CLIK-23 repeat, forms an independent actin-binding site (10). This finding was corroborated by Mino et al. (11) who demonstrated the direct interaction of a peptide corresponding to the first CaP repeat with actin in vitro. A survey of the available data bases identified other proteins with CLIK-23 repeats, in particular the Caenorhabditis elegans body wall muscle protein UNC-87 that exhibits seven tandem CLIK-23 repeats (12). A protein with a similar molecular structure has also been described by Irvine et al. (13) in the filar...

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“…Their interaction with actin filaments is an essential condition for the regulation of the actin-myosin machinery [1,2]. Calponins consist of a unique N-terminal domain followed by one to three calponin repeats.…”

Section: Introductionmentioning

confidence: 99%