Retrograde flow is a form of cell motility that is mediated by the actin cytoskeleton and is widespread in eukaryotic cells. The flow process involves the continual movement of the lamellipodial plasma membrane, membrane proteins and underlying actin cytoskeleton from the cell periphery towards the cell center. This phenomenon has been indicated as being important in cellular translocation, in the targeting of cellular migrations, in cell-substrate interactions, and in modulating the crosstalk between actin and microtubules. Retrograde flow has been extensively studied in only a few cell types (particularly neurons and mammalian and amphibian tissue culture cells) and, despite these efforts, the exact mechanism and regulation of this fundamental process is still largely unknown. The objective of this proposal is to expand the knowledge of the mechanisms underlying retrograde flow using a unique experimental model, the sea urchin coelomocyte. These cells display a highly exaggerated form of retrograde flow and possess a number of attributes which make them well suited for this study, including their optical properties, the availability of immunological probes for cytoskeletal proteins, and the readiness with which flow can be started and stopped and the cytoskeletal organization can be altered. Light and electron microscopic methods, combined with pharmacological and micromanipulation approaches will be used to address the following Specific Aims: 1. To determine the structural and functional relationships between actin filaments and actin-binding and motor proteins in the context of coelomocyte retrograde flow 2. To elucidate the physical forces operating in the context of coelomocyte retrograde flow. 3. To analyze the structural and functional relationships between actin filaments and microtubules in the context of coelomocyte retrograde flow. 4. To study the inducible transformation of coelomocytes from a lamellipodial to a filopodial form.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Academic Research Enhancement Awards (AREA) (R15)
Project #
2R15GM060925-02
Application #
6849606
Study Section
Cell Development and Function Integrated Review Group (CDF)
Program Officer
Deatherage, James F
Project Start
2000-06-01
Project End
2009-01-31
Budget Start
2005-02-01
Budget End
2009-01-31
Support Year
2
Fiscal Year
2005
Total Cost
$199,242
Indirect Cost
Name
Dickinson College
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
003029253
City
Carlisle
State
PA
Country
United States
Zip Code
17013
Henson, John H; Gianakas, Anastasia D; Henson, Lauren H et al. (2014) Broadening the spectrum of actin-based protrusive activity mediated by Arp2/3 complex-facilitated polymerization: motility of cytoplasmic ridges and tubular projections. Cytoskeleton (Hoboken) 71:484-500
Smith, L Courtney; Ghosh, Julie; Buckley, Katherine M et al. (2010) Echinoderm immunity. Adv Exp Med Biol 708:260-301
Henson, John H; Cheung, David; Fried, Christopher A et al. (2009) Structure and dynamics of an Arp2/3 complex-independent component of the lamellipodial actin network. Cell Motil Cytoskeleton 66:679-92
Henson, John H; Fried, Christopher A; McClellan, Mary K et al. (2008) Bipolar, anastral spindle development in artificially activated sea urchin eggs. Dev Dyn 237:1348-58
Brockton, Virginia; Henson, John H; Raftos, David A et al. (2008) Localization and diversity of 185/333 proteins from the purple sea urchin--unexpected protein-size range and protein expression in a new coelomocyte type. J Cell Sci 121:339-48
Henson, John H; Kolnik, Sarah E; Fried, Christopher A et al. (2003) Actin-based centripetal flow: phosphatase inhibition by calyculin-A alters flow pattern, actin organization, and actomyosin distribution. Cell Motil Cytoskeleton 56:252-66
Henson, John H; Nazarian, Ronniel; Schulberg, Katrina L et al. (2002) Wound closure in the lamellipodia of single cells: mediation by actin polymerization in the absence of an actomyosin purse string. Mol Biol Cell 13:1001-14