CH domains revisited

Stradal, Theresia E. B.; Kranewitter, Wolfgang; Winder, Steven J.; Gimona, Mario

doi:10.1016/s0014-5793(98)00751-0

Cited by 120 publications

(97 citation statements)

References 20 publications

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“…35). It is, however, worth noting that the C. elegans genome contains proteins closely related to the SM22-like members of the CaP family (consisting of a single copy of both a CLIK-23 repeat and a single N-terminal calponin homology domain) but also Vav and IQGAP-like proteins harboring a single calponin homology domain (8,9) and no CLIK-23 module. Thus, UNC-87 may be a CaP ortholog specialized for actin filament assembly processes in invertebrate obliquely striated muscle.…”

Section: Unc-87 Is An Actin-bundling Proteinmentioning

confidence: 99%

“…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.…”

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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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Section: Unc-87 Is An Actin-bundling Proteinmentioning

confidence: 99%

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confidence: 99%

UNC-87 Is an Actin-bundling Protein

Kranewitter

Ylänne

Gimona

2001

Journal of Biological Chemistry

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“…Proteins containing the CH domain are categorized into three groups: (1) the fimbrin family of monometric actincross linking molecules which contain two actinbinding domains; (2) diametric cross linking proteins and monometric F-actin binding proteins each of which contains one actin-binding domain, and (3) proteins containing a single amino-terminal CH domain (Stradal et al, 1998). According to the categorization indicated above, HELAD1 is classified into the third group that includes calponin, a molecule involved in contraction of smooth muscle, IQGAP, a signaling molecule, and the proto-oncogene Vav.…”

Section: Discussionmentioning

confidence: 99%

Isolation of HELAD1, a novel human helicase gene up-regulated in colorectal carcinomas

et al. 2002

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To investigate the mechanisms of colorectal carcinogenesis, we searched for genes regulated by adenomatous polyposis coli gene product (APC) and identified a novel gene, termed HELAD1 (helicase, APC down-regulated 1). A recombinant polypeptide representing the ATPases associated with cellular activities (AAA) domain of the HELAD1 product showed 3' to 5' helicase activity and exonuclease activity in vitro. HELAD1 was abundantly expressed in 16 of 20 colon cancers examined but hardly detectable in corresponding non-cancerous mucosae. Treatment of colon-cancer cells with antisense oligonucleotides suppressed its expression and induced apoptosis. These data revealed an importance of HELAD1 in colorectal carcinogenesis and suggest that suppression of HELAD1 may be a promising therapeutic strategy.

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“…In addition, both calponin and a -actinin contain one or two calponin homology domains (CH domains) that, at least in the case of a -actinin, are directly involved in the binding of these ABPs to actin (7,17). Therefore, we would expect mutual exclusion of these ABPs from actin laments.…”

Section: Discussionmentioning

confidence: 99%

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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CH domains revisited

Cited by 120 publications

References 20 publications

UNC-87 Is an Actin-bundling Protein

UNC-87 Is an Actin-bundling Protein

Isolation of HELAD1, a novel human helicase gene up-regulated in colorectal carcinomas

Simultaneous Interaction of Actin With a‐Actinin and Calponin

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