The Membrane Glycoprotein gp150 Is Encoded by the lagC Gene and Mediates Cell–Cell Adhesion by Heterophilic Binding during Dictyostelium Development

Abstract

gp150 is a membrane glycoprotein which has been implicated in cell-cell adhesion in the postaggregation stages of Dictyostelium development. An analysis of its tryptic peptides by mass spectrometry has identified gp150 as the product of the lagC gene, which was previously shown to play a role in morphogenesis and cell-type specification. Antibodies raised against the GST-LagC fusion protein specifically recognized gp150 in wild-type cells and showed that it is missing in lagC-null cells. Immunolocalization studies have confirmed its enrichment in cell-cell contact regions. In mutant cells that lack the aggregation stage-specific cell adhesion molecule gp80, gp150 is expressed precociously. Moreover, these cells acquire EDTA-resistant cell-cell binding during aggregation, suggesting a role for gp150 in this process. Cells in which the genes encoding gp80 and gp150 are both inactivated do not acquire EDTA-resistant cell adhesion during aggregation. Strains transformed with an actin 15::lagC construct express gp150 precociously, but do not show EDTA-resistant adhesion during early development. However, vegetative cells expressing gp150 can be recruited into aggregates of 16-h lagC-null cells. These results, together with those obtained with the cell-to-substratum binding assay, indicate that gp150 mediates cell-cell adhesion via heterophilic interactions with another component that accumulates during the aggregation stage.

Allorecognition, via TgrB1 and TgrC1, mediates the transition from unicellularity to multicellularity in the social amoebae Dictyostelium discoideum

“…The allorecognition proteins TgrB1 and TgrC1 are polymorphic in natural populations and mediate heterotypic cell-cell adhesion (Wang et al, 2000;Benabentos et al, 2009;Chen et al, 2013Chen et al, , 2014. Thus, the TgrB1 and TgrC1 proteins provide a possible mechanism for the cooperation that has been described in this system (Buss, 1982;Mehdiabadi et al, 2006;Gilbert et al, 2007;Ostrowski et al, 2008).…”

The cell adhesion molecule DdCAD-1 regulates morphogenesis through differential spatiotemporal expression inDictyostelium discoideum

“…The influence of the cadA gene on cell behavior in chimeras appears to rely on an intricate balance in the expression of the various cell adhesion molecules. As the loss of csA expression elicits the precocious expression of TgrC1 in csaA-knockout cells (Wang et al, 2000), it is conceivable that this phenomenon might also account for the behavior of the csaA gene in chimeras of csaA -cells and wild-type cells (Queller et al, 2003). The influence of cadA on cell sorting is also corroborated by rescue studies.…”

“…The Ca 2+ -dependent cell-cell contact sites are mediated by the adhesion molecule DdCAD-1 (also known previously as gp24), which is encoded by the cadA gene and expressed soon after the initiation of development (Brar and Siu, 1993;Wong et al, 1996;Wong et al, 2002;Yang et al, 1997). The Ca 2+ /Mg 2+ -independent contact sites are mediated by csA (gp80) (Harris and Siu, 2002;Kamboj et al, 1989;Siu et al, 1985;Stein and Gerisch, 1996) and TgrC1 (LagC, gp150) (Dynes et al, 1994;Gao et al, 1992;Wang et al, 2000), and they contribute to the formation of stable cell-cell adhesion during the aggregation phase and the post-aggregation phase, respectively.…”

Regulation of Rap1 activity is required for differential adhesion, cell-type patterning and morphogenesis inDictyostelium

“…To date, several different adhesion systems have been characterised through gene knockout and overexpression studies in Dictyostelium (Coates et al, 2002;Cornillon et al, 2006;Ginger et al, 1998;Harloff et al, 1989;Wang et al, 2000;Wong et al, 2002). Although these include cadherin and adherens junction systems, none of these appear to explain the defects we describe.…”