Regulated membrane recruitment of dynamin-2 mediated by sorting nexin 9.
The endocytic proteins sorting nexin 9 (SNX9) and dynamin-2 (Dyn2) assemble in the cytosol as a resting complex, together with a 41-kDa protein. We show here that the complex can be activated for membrane binding of SNX9 and Dyn2 by incubation of cytosol in the presence of ATP. SNX9 was essential for Dyn2 recruitment, whereas the reverse was not the case. RNA interference experiments confirmed that SNX9 functions as a mediator of Dyn2 recruitment to membranes in cells. The 41-kDa component was identified as the glycolytic enzyme aldolase. Aldolase bound with high affinity to a tryptophan-containing acidic sequence in SNX9 located close to its Phox homology domain, thereby blocking the membrane binding activity of SNX9. Phosphorylation of SNX9 released aldolase from the native cytosolic complex and rendered SNX9 competent for membrane binding. The results suggest that SNX9-dependent recruitment of Dyn2 to the membrane is regulated by an interaction between SNX9 and aldolase.
Department of Medical Biochemistry and Biophysics, Umeå University, S-901 87 Umeå, Sweden.
Richard
R
Lundmark
Sven R
SR
Carlsson
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D034285:Dynamin II / Q000378:metabolism*; D004705:Endocytosis; D005634:Fructose-Bisphosphate Aldolase / Q000378:metabolism; D006019:Glycolysis; D006367:HeLa Cells; D006801:Humans; D020014:K562 Cells; D008081:Liposomes / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D011485:Protein Binding; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry; D058305:Sorting Nexins; D013696:Temperature; D014162:Transfection; D033921:Vesicular Transport Proteins
D002352:Carrier Proteins; D008081:Liposomes; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; C400533:SNX9 protein, human; D058305:Sorting Nexins; D033921:Vesicular Transport Proteins; D000255:Adenosine Triphosphate; D034285:Dynamin II; D005634:Fructose-Bisphosphate Aldolase