Show simple item record

dc.contributor.authorChoe, Jonathan M.
Bakthavatsalam, Deenadayalan
Phillips, Jonathan E.
Gomer, Richard H.
dc.date.accessioned 2016-02-03T18:41:17Z
dc.date.available 2016-02-03T18:41:17Z
dc.date.issued 2009
dc.identifier.citation Choe, Jonathan M., Bakthavatsalam, Deenadayalan, Phillips, Jonathan E., et al.. "Dictyostelium cells bind a secreted autocrine factor that represses cell proliferation." BMC Biochemistry, 10, (2009) BioMed Central: http://dx.doi.org/10.1186/1471-2091-10-4.
dc.identifier.urihttps://hdl.handle.net/1911/88325
dc.description.abstract Background: Dictyostelium cells secrete the proteins AprA and CfaD. Cells lacking either AprA or CfaD proliferate faster than wild type, while AprA or CfaD overexpressor cells proliferate slowly, indicating that AprA and CfaD are autocrine factors that repress proliferation. CfaD interacts with AprA and requires the presence of AprA to slow proliferation. To determine if CfaD is necessary for the ability of AprA to slow proliferation, whether AprA binds to cells, and if so whether the binding requires the presence of CfaD, we examined the binding and effect on proliferation of recombinant AprA. Results: We find that the extracellular accumulation of AprA increases with cell density and reaches a concentration of 0.3 μg/ml near a stationary cell density. When added to wild-type or aprA- cells, recombinant AprA (rAprA) significantly slows proliferation at 0.1 μg/ml and higher concentrations. From 4 to 64 μg/ml, the effect of rAprA is at a plateau, slowing but not stopping proliferation. The proliferation-inhibiting activity of rAprA is roughly the same as that of native AprA in conditioned growth medium. Proliferating aprA- cells show saturable binding of rAprA to 92,000 ± 11,000 cell-surface receptors with a K D of 0.03 ± 0.02 μg/ml. There appears to be one class of binding site, and no apparent cooperativity. Native AprA inhibits the binding of rAprA to aprA- cells with a K i of 0.03 μg/ml, suggesting that the binding kinetics of rAprA are similar to those of native AprA. The proliferation of cells lacking CrlA, a cAMP receptor-like protein, or cells lacking CfaD are not affected by rAprA. Surprisingly, both cell types still bind rAprA. Conclusion: Together, the data suggest that AprA functions as an autocrine proliferation-inhibiting factor by binding to cell surface receptors. Although AprA requires CfaD for activity, it does not require CfaD to bind to cells, suggesting the possibility that cells have an AprA receptor and a CfaD receptor, and activation of both receptors is required to slow proliferation. We previously found that crlA- cells are sensitive to CfaD. Combined with the results presented here, this suggests that CrlA is not the AprA or CfaD receptor, and may be the receptor for an unknown third factor that is required for AprA and CfaD activity.
dc.publisher BioMed Central
dc.rights Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
dc.title Dictyostelium cells bind a secreted autocrine factor that represses cell proliferation
dc.type Journal article
dc.citation.journalTitle BMC Biochemistry
dc.citation.volumeNumber 10
dc.date.updated 2016-02-03T18:41:17Z
dc.type.dcmi Text
dc.identifier.doihttp://dx.doi.org/10.1186/1471-2091-10-4
dc.language.rfc3066 en
dc.type.publication publisher version
dc.rights.holder Choe et al.
local.sword.agent BioMed Central
dc.citation.articleNumber 4


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record