ATP-Binding Cassette Transporter B4 Anchors the Cell Adhesion Molecule DdCAD-1 to Cell Membrane in Dictyostelium discoideum

Abstract

In Dictyostelium, soluble cell adhesion molecule, DdCAD-1, regulates cell-cell interaction through an unknown anchoring protein on the plasma membrane. Far western blot analysis using different probes revealed that the potential DdCAD-1 interacting protein was between 64 and 98 kDa. To isolate and identify the anchoring protein, GST-DdCAD-1 and anchoring protein were cross-linked in vivo by chemical cross-linker and stable protein complex was isolated by co-immunoprecipitation assays. The protein cross-linked to DdCAD-1 was extracted from the gel slice and trypsinized. The peptides were subjected to analysis by mass spectrometry, which showed that the putative anchoring protein belongs to ATP-binding cassette transporter family.

Aberrant adhesion impacts early development in aDictyosteliummodel for juvenile neuronal ceroid lipofuscinosis

“…57,65 The protein localizes to the external surface of the plasma membrane and links to the membrane via the ABC (ATP-binding cassette) transporter, AbcB4. 55,66 Coupled with the finding that GFP-Cln3 localizes predominantly to the CV system, these observations indicate that Cln3 may negatively affect CadA secretion. Alternatively, it is also possible that Cln3 may be required for the tethering of CadA to the cell membrane.…”

Interface interactions between βγ‐crystallin domain and Ig‐like domain render Ca2+‐binding site inoperative in abundant perithecial protein of Neurospora crassa

“…However, there is no known interacting partner of APP. APP homolog DdCAD‐1 is known to bind calmodulin [which assists the import of DdCAD‐1 to the contractile vacuole (Sriskanthadevan et al ., )], and ATP‐binding cassette transporter B4 [which helps DdCAD‐1 to anchor to the cell membrane (Yang et al ., )]. DdCAD‐1 has also been shown to undergo phosphorylation by RasG protein (Secko et al ., ).…”

“…The initial cell‐cell contacts during aggregation of Dictyostelium are facilitated by DdCAD‐1, a function proposed to be analogous to that of animal cadherins (Wong et al ., ; Lin et al ., ; Abedin and King, ). DdCad‐1 is expressed as a cytosolic soluble protein which is transported to the plasma membrane by contractile vacuoles (Sesaki et al ., ), where it tethers to a transmembrane protein associated with cytoskeletal elements (Yang et al ., ). In the post‐aggregation stage, DdCAD‐1 is completely internalized (Sesaki et al ., ).…”