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DTSTART:20190331T030000
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DTSTART:20191027T020000
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DTSTAMP:20260404T110157Z
UID:5dad50dc04c4c227393698@ist.ac.at
DTSTART:20191023T110000
DTEND:20191023T123000
DESCRIPTION:Speaker: Bolger-Munro\, Madison\nhosted by Carl-Philipp Heisenb
 erg\nAbstract: When B cells encounter antigens on the surface of an antige
 n-presenting cell (APC)\, B cell receptors (BCRs) are gathered into microc
 lusters that recruit signalling enzymes. These microclusters then move cen
 tripetally and coalesce into the central supramolecular activation cluster
  of an immune synapse. The mechanisms controlling BCR organization during 
 immune synapse formation\, and how this impacts BCR signalling\, are not f
 ully understood. We show that this coalescence of BCR microclusters depend
 s on the actin-related protein 2/3 (Arp2/3) complex\, which nucleates bran
 ched actin networks. Moreover\, in murine B cells\, this dynamic spatial r
 eorganization of BCR microclusters amplifies proximal BCR signalling react
 ions and enhances the ability of membrane-associated antigens to induce tr
 anscriptional responses and proliferation. Our finding that Arp2/3 complex
  activity is important for B cell responses to spatially restricted membra
 ne-bound antigens\, but not for soluble antigens\, highlights a critical r
 ole for Arp2/3 complex-dependent actin remodeling in B cell responses to A
 PC-bound antigens. These findings indicate that Arp2/3-dependent actin ret
 rograde flow amplifies microcluster-based BCR signalling. However\, the un
 derlying mechanism is not known. Because the BCR is a mechanosenstive rece
 ptor\, we are now testing the hypothesis that Arp2/3 activity generates fo
 rce that is exerted on antigen-bound BCRs and that this increases BCR sign
 alling output and promotes antigen internalization.
LOCATION:Meeting room 2nd floor / Bertalanffy Bldg. (I04.2OG - LAB)\, ISTA
ORGANIZER:lalesch@ist.ac.at
SUMMARY:Bolger-Munro\, Madison: Cytoskeletal regulation of B cell receptor 
 (BCR) spatial organization and signalling
URL:https://talks-calendar.ista.ac.at/events/2368
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