Uncovering a role for the tail of the dictyostelium discoideum sada protein in cell-substrate adhesion

Anthony S. Kowal, Rex L. Chisholm

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Previous work from our laboratory showed that the Dictyostelium discoideum SadA protein plays a central role in cell-substrate adhesion. SadA null cells exhibit a loss of adhesion, a disrupted actin cytoskeleton, and a cytokinesis defect. How SadA mediates these phenotypes is unknown. This work addresses the mechanism of SadA function, demonstrating an important role for the C-terminal cytoplasmic tail in SadA function. We found that a SadA tailless mutant was unable to rescue the sadA adhesion deficiency, and overexpression of the SadA tail domain reduced adhesion in wild-type cells. We also show that SadA is closely associated with the actin cytoskeleton. Mutagenesis studies suggested that four serine residues in the tail, S924/S925 and S940/ S941, may regulate association of SadA with the actin cytoskeleton. Glutathione S-transferase pull-down assays identified at least one likely interaction partner of the SadA tail, cortexillin I, a known actin bundling protein. Thus, our data demonstrate an important role for the carboxy-terminal cytoplasmic tail in SadA function and strongly suggest that a phosphorylation event in this tail regulates an interaction with cortexillin I. Based on our data, we propose a model for the function of SadA.

Original languageEnglish (US)
Pages (from-to)662-671
Number of pages10
JournalEukaryotic Cell
Issue number5
StatePublished - May 2011

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology


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