Functional Interactions between the p35 Subunit of the Arp2/3 Complex and Calmodulin in Yeast

Schaerer-Brodbeck, Claudia; Riezman, Howard

doi:10.1091/mbc.11.4.1113

Cited by 43 publications

(58 citation statements)

References 61 publications

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“…In this study, to obtain a value for the number of Arp2/3 complex molecules per patch in living cells, we labeled either the ArpC5-Arc15 or the ArpC2-Arc35 subunit. Previous studies have established that these fusion proteins are functional (Kaksonen et al, 2003;Schaerer-Brodbeck and Riezman, 2000). Both probes gave us similar results, with the number of Arp2/3 molecules per patch of ~95.…”

Section: Molecular Stoichiometry Of Coronin Cofilin and Aip1supporting

confidence: 67%

Overlapping and distinct functions for cofilin, coronin and Aip1 in actin dynamics in vivo

Lin

Galletta

Sept

et al. 2010

Journal of Cell Science

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SummaryActin-filament disassembly is crucial for actin-based motility, to control filament network architecture and to regenerate subunits for assembly. Here, we examined the roles of three actin cytoskeletal proteins, coronin, cofilin and Aip1, which have been suggested to combine in various ways to control actin dynamics by promoting or regulating disassembly. We studied their functions during the endocytosis process in budding yeast, where actin-filament dynamics at the cortical actin 'patch' contribute to the formation and movement of endocytic vesicles. We found that all three proteins were recruited during the late phase of the life of the actin patch. They all arrived at the same time, when actin and other actin-associated proteins were leaving the patch. Cofilin point mutations influenced the localization of coronin and Aip1, but the complete loss of coronin had no effect on localization of cofilin or Aip1. Using quantitative patch motion analysis and comparing mutant alleles, the phenotypes for mutations of the three genes showed some commonalities, but also some striking differences. Cofilin was clearly the most important; it displayed the most severe mutant phenotypes affecting actin-patch assembly and movement. Together, the results suggest that all three proteins work together to promote actin disassembly, but not in a simple way, and not with equal importance.

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Section: Molecular Stoichiometry Of Coronin Cofilin and Aip1supporting

confidence: 67%

Overlapping and distinct functions for cofilin, coronin and Aip1 in actin dynamics in vivo

Lin

Galletta

Sept

et al. 2010

Journal of Cell Science

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“…This complex, which comprises a total of six proteins, is involved in endocytosis and actin cytoskeleton organization. 45 The expression pro®les of ARC35 and ARP3 show a time-delayed relationship, with the expression of ARC35 being one time point (20 minutes) delayed compared to ARP3. This ®ts in well with Arc35p being required late in G1 for the cytoskeleton-organization functionality.…”

Section: Strongly Documented Suggested Relationshipmentioning

confidence: 97%

Beyond synexpression relationships: local clustering of time-shifted and inverted gene expression profiles identifies new, biologically relevant interactions

Qian

Dolled‐Filhart

Lin

et al. 2001

Journal of Molecular Biology

171

146

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The complexity of biological systems provides for a great diversity of relationships between genes. The current analysis of whole-genome expression data focuses on relationships based on global correlation over a whole time-course, identifying clusters of genes whose expression levels simultaneously rise and fall. There are, of course, other potential relationships between genes, which are missed by such global clustering. These include activation, where one expects a time-delay between related expression pro®les, and inhibition, where one expects an inverted relationship. Here, we propose a new method, which we call local clustering, for identifying these time-delayed and inverted relationships. It is related to conventional gene-expression clustering in a fashion analogous to the way local sequence alignment (the Smith-Waterman algorithm) is derived from global alignment (Needleman-Wunsch). An integral part of our method is the use of random score distributions to assess the statistical signi®cance of each cluster. We applied our method to the yeast cellcycle expression dataset and were able to detect a considerable number of additional biological relationships between genes, beyond those resulting from conventional correlation. We related these new relationships between genes to their similarity in function (as determined from the MIPS scheme) or their having known protein-protein interactions (as determined from the large-scale two-hybrid experiment); we found that genes strongly related by local clustering were considerably more likely than random to have a known interaction or a similar cellular role. This suggests that local clustering may be useful in functional annotation of uncharacterized genes. We examined many of the new relationships in detail. Some of them were already well-documented examples of inhibition or activation, which provide corroboration for our results. For instance, we found an inverted expression pro®le relationship between genes YME1 and YNT20, where the latter has been experimentally documented as a bypass suppressor of the former. We also found new relationships involving uncharacterized yeast genes and were able to suggest functions for many of them. In particular, we found a timedelayed expression relationship between J0544 (which has not yet been functionally characterized) and four genes associated with the mitochondria. This suggests that J0544 may be involved in the control or activation of mitochondrial genes. We have also looked at other, less extensive datasets than the yeast cell-cycle and found further interesting relationships. Our clustering program and a detailed website of clustering results is available at

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“…It also raises an important mechanistic question: how do cables and not patches selectively become decorated with Tpm1 and Tpm2? Another factor that may regulate Arp2/3 complex function is Cmd1 (calmodulin), which interacts both genetically and biochemically with the ARPC2/p35 subunit (330). There are likely many other cellular factors that must be coordinated with NPFs and Crn1 to control Arp2/3 complex function.…”

Section: Assembly Of Actin At Cortical Patchesmentioning

confidence: 99%

“…Thus, additional investigations are needed to resolve this potential Arp2/3 complex function at cytokinetic rings. Finally, separate from assembly of the three major actin structures-patches, cables, and rings-Arp2/3 complex function contributes to organelle inheritance, nuclear export, and mitotic spindle orientation (41,330,331,416). Understanding the mechanistic basis of these functions could broaden the range of action for the Arp2/3 complex.…”

Section: Assembly Of Actin At Cortical Patchesmentioning

confidence: 99%

The Yeast Actin Cytoskeleton: from Cellular Function to Biochemical Mechanism

Moseley

Goode

2006

Microbiol Mol Biol Rev

360

427

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SUMMARY All cells undergo rapid remodeling of their actin networks to regulate such critical processes as endocytosis, cytokinesis, cell polarity, and cell morphogenesis. These events are driven by the coordinated activities of a set of 20 to 30 highly conserved actin-associated proteins, in addition to many cell-specific actin-associated proteins and numerous upstream signaling molecules. The combined activities of these factors control with exquisite precision the spatial and temporal assembly of actin structures and ensure dynamic turnover of actin structures such that cells can rapidly alter their cytoskeletons in response to internal and external cues. One of the most exciting principles to emerge from the last decade of research on actin is that the assembly of architecturally diverse actin structures is governed by highly conserved machinery and mechanisms. With this realization, it has become apparent that pioneering efforts in budding yeast have contributed substantially to defining the universal mechanisms regulating actin dynamics in eukaryotes. In this review, we first describe the filamentous actin structures found in Saccharomyces cerevisiae (patches, cables, and rings) and their physiological functions, and then we discuss in detail the specific roles of actin-associated proteins and their biochemical mechanisms of action.

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Functional Interactions between the p35 Subunit of the Arp2/3 Complex and Calmodulin in Yeast

Cited by 43 publications

References 61 publications

Overlapping and distinct functions for cofilin, coronin and Aip1 in actin dynamics in vivo

Overlapping and distinct functions for cofilin, coronin and Aip1 in actin dynamics in vivo

Beyond synexpression relationships: local clustering of time-shifted and inverted gene expression profiles identifies new, biologically relevant interactions

The Yeast Actin Cytoskeleton: from Cellular Function to Biochemical Mechanism

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