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A SAP domain-containing protein shuttles between the nucleus and cell membranes and plays a role in adhesion and migration in D. discoideum

The AmpA protein reduces cell adhesion, thereby influencing cell migration in Dictyostelium. To understand how ampA influences cell migration, second site suppressors of an AmpA overexpressing cell line were created by REMI mutagenesis. Mutant candidates were identified by their ability to suppress...

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Detalles Bibliográficos
Autores principales: Kelsey, Jessica S., Blumberg, Daphne D.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Company of Biologists 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3625868/
https://www.ncbi.nlm.nih.gov/pubmed/23616924
http://dx.doi.org/10.1242/bio.20133889
Descripción
Sumario:The AmpA protein reduces cell adhesion, thereby influencing cell migration in Dictyostelium. To understand how ampA influences cell migration, second site suppressors of an AmpA overexpressing cell line were created by REMI mutagenesis. Mutant candidates were identified by their ability to suppress the large plaques that the AmpA overexpressing cells form on bacterial lawns as a result of their increased rate of migration. One suppressor gene, sma, encodes an uncharacterized protein, which contains a SAP DNA-binding domain and a PTEN-like domain. Using sma gene knockouts and Sma-mRFP expressing cell lines, a role for sma in influencing cell migration was uncovered. Knockouts of the sma gene in a wild-type background enhanced chemotaxis. An additional role for Sma in influencing cell–cell adhesion was also demonstrated. Sma protein transitions between cytosolic and nuclear localizations as a function of cell density. In growing cells migrating to folic acid it is localized to regions of actin polymerization and absent from the nucleus. A role for Sma in influencing ampA mRNA levels is also demonstrated. Sma additionally appears to be involved in ampA pathways regulating cell size, actin polymerization, and cell substrate adhesion. We present insights to the SAP domain-containing group of proteins in Dictyostelium and provide evidence of a role for a SAP domain-containing protein shuttling from the nucleus to sites of actin polymerization during chemotaxis to folic acid and influencing the efficiency of migration.