TY - JOUR AU - Gombos, Rita I AU - Migh, Ede AU - Antal, Otilia Tamara AU - Mukherjee, A AU - Jenny, A AU - Mihály, József TI - The Formin DAAM Functions as Molecular Effector of the Planar Cell Polarity Pathway during Axonal Development in Drosophila JF - JOURNAL OF NEUROSCIENCE J2 - J NEUROSCI VL - 35 PY - 2015 IS - 28 SP - 10154 EP - 10167 PG - 14 SN - 0270-6474 DO - 10.1523/JNEUROSCI.3708-14.2015 UR - https://m2.mtmt.hu/api/publication/2931297 ID - 2931297 AB - Recent studies established that the planar cell polarity (PCP) pathway is critical for various aspects of nervous system development and function, including axonal guidance. Although it seems clear that PCP signaling regulates actin dynamics, the mechanisms through which this occurs remain elusive. Here, we establish a functional link between the PCP system and one specific actin regulator, the formin DAAM, which has previously been shown to be required for embryonic axonal morphogenesis and filopodia formation in the growth cone. We show that dDAAM also plays a pivotal role during axonal growth and guidance in the adult Drosophila mushroom body, a brain center for learning and memory. By using a combination of genetic and biochemical assays, we demonstrate that Wnt5 and the PCP signaling proteins Frizzled, Strabismus, and Dishevelled act in concert with the small GTPase Rac1 to activate the actin assembly functions of dDAAM essential for correct targeting of mushroom body axons. Collectively, these data suggest that dDAAM is used as a major molecular effector of the PCP guidance pathway. By uncovering a signaling system from the Wnt5 guidance cue to an actin assembly factor, we propose that the Wnt5/PCP navigation system is linked by dDAAM to the regulation of the growth cone actin cytoskeleton, and thereby growth cone behavior, in a direct way. LA - English DB - MTMT ER - TY - JOUR AU - Molnár, Imre Árpád AU - Migh, Ede AU - Szikora, Szilárd AU - Kalmár, Tibor AU - Végh, Attila Gergely AU - Deák, Ferenc AU - Barkó, Szilvia AU - Bugyi, Beáta AU - Orfanos, Zacharias AU - Kovács, János AU - Juhász, Gábor AU - Váró, György AU - Nyitrai, Miklós AU - Sparrow, John AU - Mihály, József TI - DAAM is required for thin filament formation and sarcomerogenesis during muscle development in Drosophila JF - PLOS GENETICS J2 - PLOS GENET VL - 10 PY - 2014 IS - 2 PG - 15 SN - 1553-7390 DO - 10.1371/journal.pgen.1004166 UR - https://m2.mtmt.hu/api/publication/2506301 ID - 2506301 AB - During muscle development, myosin and actin containing filaments assemble into the highly organized sarcomeric structure critical for muscle function. Although sarcomerogenesis clearly involves the de novo formation of actin filaments, this process remained poorly understood. Here we show that mouse and Drosophila members of the DAAM formin family are sarcomere-associated actin assembly factors enriched at the Z-disc and M-band. Analysis of dDAAM mutants revealed a pivotal role in myofibrillogenesis of larval somatic muscles, indirect flight muscles and the heart. We found that loss of dDAAM function results in multiple defects in sarcomere development including thin and thick filament disorganization, Z-disc and M-band formation, and a near complete absence of the myofibrillar lattice. Collectively, our data suggest that dDAAM is required for the initial assembly of thin filaments, and subsequently it promotes filament elongation by assembling short actin polymers that anneal to the pointed end of the growing filaments, and by antagonizing the capping protein Tropomodulin. LA - English DB - MTMT ER - TY - JOUR AU - Rees, EJ AU - Erdélyi, Miklós AU - Schierle, GSK AU - Knight, A AU - Kaminski, CF TI - Elements of image processing in localization microscopy JF - JOURNAL OF OPTICS J2 - J OPTICS-UK VL - 15 PY - 2013 IS - 9 PG - 7 SN - 2040-8978 DO - 10.1088/2040-8978/15/9/094012 UR - https://m2.mtmt.hu/api/publication/2588376 ID - 2588376 N1 - Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, CB2 3RA Cambridge, United Kingdom Analytical Science Division, National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, United Kingdom Cited By :25 Export Date: 25 May 2020 Correspondence Address: Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, CB2 3RA Cambridge, United Kingdom Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, CB2 3RA Cambridge, United Kingdom Analytical Science Division, National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, United Kingdom Cited By :27 Export Date: 23 June 2020 Correspondence Address: Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, CB2 3RA Cambridge, United Kingdom LA - English DB - MTMT ER - TY - JOUR AU - Barkó, Szilvia AU - Bugyi, Beáta AU - Carlier, MF AU - Gombos, Rita I AU - Matusek, Tamás AU - Mihály, József AU - Nyitrai, Miklós TI - Characterization of the biochemical properties and biological function of the formin homology domains of Drosophila DAAM. JF - JOURNAL OF BIOLOGICAL CHEMISTRY J2 - J BIOL CHEM VL - 285 PY - 2010 IS - 17 SP - 13154 EP - 13169 PG - 16 SN - 0021-9258 DO - 10.1074/jbc.M109.093914 UR - https://m2.mtmt.hu/api/publication/1343165 ID - 1343165 AB - We characterized the properties of Drosophila melanogaster DAAM-FH2 and DAAM-FH1-FH2 fragments and their interactions with actin and profilin by using various biophysical methods and in vivo experiments. The results show that although the DAAM-FH2 fragment does not have any conspicuous effect on actin assembly in vivo, in cells expressing the DAAM-FH1-FH2 fragment, a profilin-dependent increase in the formation of actin structures is observed. The trachea-specific expression of DAAM-FH1-FH2 also induces phenotypic effects, leading to the collapse of the tracheal tube and lethality in the larval stages. In vitro, both DAAM fragments catalyze actin nucleation but severely decrease both the elongation and depolymerization rate of the filaments. Profilin acts as a molecular switch in DAAM function. DAAM-FH1-FH2, remaining bound to barbed ends, drives processive assembly of profilin-actin, whereas DAAM-FH2 forms an abortive complex with barbed ends that does not support profilin-actin assembly. Both DAAM fragments also bind to the sides of the actin filaments and induce actin bundling. These observations show that the D. melanogaster DAAM formin represents an extreme class of barbed end regulators gated by profilin. LA - English DB - MTMT ER - TY - JOUR AU - Matusek, Tamás AU - Djiane, A AU - Jankovics, Ferenc AU - Brunner, D AU - Mlodzik, M AU - Mihály, József TI - The Drosophila formin DAAM regulates the tracheal cuticle pattern through organizing the actin cytoskeleton JF - DEVELOPMENT J2 - DEVELOPMENT VL - 133 PY - 2006 SP - 957 EP - 966 PG - 10 SN - 0950-1991 DO - 10.1242/dev.02266 UR - https://m2.mtmt.hu/api/publication/1914506 ID - 1914506 LA - English DB - MTMT ER - TY - JOUR AU - Trombitás, Károly AU - Granzier, H TI - Actin removal from cardiac myocytes shows that near Z line titin attaches to actin while under tension JF - AMERICAN JOURNAL OF PHYSIOLOGY: CELL PHYSIOLOGY J2 - AM J PHYSIOL CELL PH VL - 273 PY - 1997 IS - 2 SP - C662 EP - C670 SN - 0363-6143 UR - https://m2.mtmt.hu/api/publication/1322352 ID - 1322352 AB - The I band of cardiac sarcomeres contains both actin and titin/connectin filaments. Earlier work has suggested that titin binds to actin in situ. This interaction must be weak in the region of the I band where titin behaves elastically. On the other hand, titin may bind strongly to actin in the similar to 100-nm-wide region adjoining the Z line, where titin has been found to be inelastic. To study the putative interaction between titin and actin, techniques for selective removal of actin from different regions of the I band are needed. Here we report studies with a gelsolin fragment (FX-45) and extract actin from rat cardiac myocytes. Actin extraction was biphasic: the majority of actin was extracted in similar to 10 min, whereas actin near the Z line (where titin is inelastic) required a similar to 10-fold longer extraction time. Thus, by controlling the extraction time, we could remove either the full actin filament outside the Z line or just the segment of the actin filament that extends beyond the inelastic region of titin that adjoins the Z line. The actin filament-free I band contained titin filaments, typically with one filament extending from each thick filament. In addition, we observed a dark transverse line (junction line), the location of which in the sarcomere varied linearly with sarcomere length. The position in the sarcomere of the junction line coincided with the binding site of the anti-titin antibody 9D10. Actin removal significantly affected the slack sarcomere length. Slack sarcomere length was 1.85 +/- 0.04 mu m in control cells and decreased to 1.71 +/- 0.05 mu m after actin near the Z line was extracted. This length reduction may be caused by contraction of the titin segment that becomes exposed after actin removal near the Z line, indicating that titin is not only attached to the actin filament but is also under tension. LA - English DB - MTMT ER -