Calponin Interaction with α-Actinin-Actin: Evidence for a Structural Role for Calponin

Leinweber, Barbara; Tang, Jay X.; Stafford, Walter F.; Chalovich, Joseph M.

doi:10.1016/s0006-3495(99)77151-1

Cited by 39 publications

(33 citation statements)

References 52 publications

(65 reference statements)

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“…This apparent contradiction may result from a nonspeci c interaction between calponin and a -actinin. However, we and others (19) have not detected any direct interaction between isolated calponin and a -actinin. Although we cannot completely exclude the possibility that after binding to actin the calponin and a -actinin start to interact with each other, such an interaction seems rather improbable for explaining the unusually high stoichiometry of ABPs bound to actin.…”

Section: Discussioncontrasting

confidence: 71%

“…However, in contrast to Leinweber et al (19), we found that under certain conditions a -actinin can partially displace calponin. This difference may be due to the fact that we polymerized G-actin in the presence of two ABPs, whereas Leinweber et al (19) titrated F-actin with ABPs. We found that the structure of the actin bundles formed in the presence of only one ABP differs from that formed in the presence of both (Fig.…”

Section: Discussionmentioning

confidence: 92%

“…While this manuscript was in preparation, the paper of Leinweber et al (19) was published. Our data mainly agree with the results of that publication.…”

Section: Discussionmentioning

confidence: 99%

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Simultaneous Interaction of Actin With a‐Actinin and Calponin

Panasenko

Gusev

2000

IUBMB Life

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SummaryInteraction of calponin and ®-actinin with actin was analyzed by means of cosedimentation and electron microscopy. G-actin was polymerized in the presence of calponin, ®-actinin, or both of these actin-binding proteins (ABPs). The single and bundled actin laments were separated, and the stoichiometry of ABPs and actin in both types of laments was determined. Binding of calponin to the single or bundled actin laments was not dependent on the presence of ®-actinin and did not displace ®-actinin from actin. In the presence of calponin, however, less ®-actinin was bound to the bundled actin laments, and the binding of ®-actinin was accompanied by a partial decrease in the calponin/actin stoichiometry in the bundles of actin laments. Calponin had no in uence on the binding of ®-actinin to the single actin laments. The structure of actin bundles formed in the presence of the two ABPs differed from that formed in the presence of either one singly. We conclude that calponin and ®-actinin can coexist on actin and that nearly each actin monomer can bind one of these ABPs. IUBMB Life, 49: 277 -282, 2000

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Section: Discussioncontrasting

confidence: 71%

Section: Discussionmentioning

confidence: 92%

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Simultaneous Interaction of Actin With a‐Actinin and Calponin

Panasenko

Gusev

2000

IUBMB Life

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“…This hypothesis is consistent with the previous observations that UNC-87 knock-out animals display distorted myofilaments (12,14). A structural role has also been postulated for CaP (10,28), which bundles filaments at low ionic strength (29). Thus, we hypothesize that the cytoskeleton-stabilizing function of CaP is contributed by the C-terminal repeats.…”

Section: Discussionmentioning

confidence: 60%

“…UNC-87 binding to actin was also unaffected by saturating concentrations of either ␣-actinin or filamin, indicating the occupation of nonoverlapping sites on the actin filament. In support of this Chalovich and colleagues (28) reported that ␣-actinin, filamin, and calponin show only little displacement and are capable of binding the actin filament simultaneously in almost stoichiometrical amounts. Thus, the second actin-binding site of CaP (ABS2) and that of UNC-87 are likely to interact with a similar region along the filament.…”

Section: Discussionmentioning

confidence: 81%

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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Smooth muscle α-actinin binds tightly to fesselin and attenuates its activity toward actin polymerization

Pham

Chalovich

2006

J Muscle Res Cell Motil

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Fesselin is an actin binding protein from smooth muscle that nucleates actin polymerization in a Ca(++)-calmodulin dependent manner, bundles actin and inhibits the actin-activated ATPase activity of myosin S1. We now report that fesselin binds to smooth muscle alpha-actinin. Binding was measured by blot overlay, affinity chromatography and sedimentation methods. Binding was moderate with an association constant of 1-4 x 10(7) M(-1) assuming a 1:1 association of fesselin with alpha-actinin. Fesselin binds to the central spectrin domain repeat region of alpha-actinin but not to the CH1-CH2 domain. Fesselin accelerates the polymerization of actin. This activity of fesselin was attenuated by alpha-actinin. These observations support the role of fesselin in organizing the cytoskeleton.

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Calponin Interaction with α-Actinin-Actin: Evidence for a Structural Role for Calponin

Cited by 39 publications

References 52 publications

Simultaneous Interaction of Actin With a‐Actinin and Calponin

Simultaneous Interaction of Actin With a‐Actinin and Calponin

UNC-87 Is an Actin-bundling Protein

Smooth muscle α-actinin binds tightly to fesselin and attenuates its activity toward actin polymerization

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