BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CMSA - ECPv6.17.1//NONSGML v1.0//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-ORIGINAL-URL:https://cmsa.fas.harvard.edu
X-WR-CALDESC:Events for CMSA
REFRESH-INTERVAL;VALUE=DURATION:PT1H
X-Robots-Tag:noindex
X-PUBLISHED-TTL:PT1H
BEGIN:VTIMEZONE
TZID:America/New_York
BEGIN:DAYLIGHT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
DTSTART:20220313T070000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
DTSTART:20221106T060000
END:STANDARD
BEGIN:DAYLIGHT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
DTSTART:20230312T070000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
DTSTART:20231105T060000
END:STANDARD
BEGIN:DAYLIGHT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
DTSTART:20240310T070000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
DTSTART:20241103T060000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20230413T130000
DTEND;TZID=America/New_York:20230413T140000
DTSTAMP:20240216T112442Z
CREATED:20230824T182821Z
LAST-MODIFIED:20240216T112442Z
UID:10001811-1681390800-1681394400@cmsa.fas.harvard.edu
SUMMARY:Control of actin cable length by decelerated growth and network geometry
DESCRIPTION:Active Matter Seminar\n\n\nSpeaker: Shane McInally\, Brandeis \nTitle: Control of actin cable length by decelerated growth and network geometry \nAbstract: The sizes of many subcellular structures are coordinated with cell size to ensure that these structures meet the functional demands of the cell. In eukaryotic cells\, these subcellular structures are often membrane-bound organelles\, whose volume is the physiologically important aspect of their size. Scaling organelle volume with cell volume can be explained by limiting pool mechanisms\, wherein a constant concentration of molecular building blocks enables subcellular structures to increase in size proportionally with cell volume. However\, limiting pool mechanisms cannot explain how the size of linear subcellular structures\, such as cytoskeletal filaments\, scale with the linear dimensions of the cell. Recently\, we discovered that the length of actin cables in budding yeast (used for intracellular transport) precisely matches the length of the cell in which they are assembled. Using mathematical modeling and quantitative imaging of actin cable growth dynamics\, we found that as the actin cables grow longer\, their extension rates slow (or decelerate)\, enabling cable length to match cell length. Importantly\, this deceleration behavior is cell-length dependent\, allowing cables in longer cells to grow faster\, and therefore reach a longer length before growth stops at the back of the cell. In addition\, we have unexpectedly found that cable length is specified by cable shape. Our imaging analysis reveals that cables progressively taper as they extend from the bud neck into the mother cell\, and further\, this tapering scales with cell length. Integrating observations made for tapering actin networks in other systems\, we have developed a novel mathematical model for cable length control that recapitulates our quantitative experimental observations. Unlike other models of size control\, this model does not require length-dependent rates of assembly or disassembly. Instead\, feedback control over the length of the cable is an emergent property due to the cross-linked and bundled architecture of the actin filaments within the cable. This work reveals a new strategy that cells use to coordinate the size of their internal parts with their linear dimensions. Similar design principles may control the size and scaling of other subcellular structures whose physiologically important dimension is their length.
URL:https://cmsa.fas.harvard.edu/event/am-41323/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Active Matter Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Active-Matter-Seminar-04.13.23.png
END:VEVENT
END:VCALENDAR