Specific role for the PH domain of dynamin-1 in the regulation of rapid endocytosis in adrenal chromaffin cells.
Dynamin plays a key role in the scission event common to various types of endocytosis. We demonstrate that the pleckstrin homology (PH) domain of dynamin-1 is critical in the process of rapid endocytosis (RE) in chromaffin cells. Introduction of this isolated PH domain into cells at concentrations as low as 1 microM completely suppressed RE. PH domains from other proteins, including that from the closely related dynamin-2, were ineffective as inhibitors, even at high concentrations. Mutational studies indicated that a pair of isoform-specific amino acids, located in a variable loop between the first two beta-strands, accounted for the differential effect of the two dynamin PH domains. Switching these amino acids in the dynamin-2 PH domain to the equivalent residues in dynamin-1 (SL-->GI) generated a molecule that blocked RE. Thus, the PH domain of dynamin-1 is essential for RE and exhibits a precise molecular selectivity. As chromaffin cells express both dynamin-1 and -2, we speculate that different isoforms of dynamin may regulate distinct endocytotic processes and that the PH domain contributes to this specificity.
Artalejo
C R
CR
Department of Neurobiology and Physiology, Northwestern University, Evanston, IL 60208, USA.
Lemmon
M A
MA
Schlessinger
J
J
Palfrey
H C
HC
D000313:Adrenal Medulla / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D001798:Blood Proteins / Q000737:chemistry*; D002417:Cattle; D019439:Chromaffin Cells / Q000502:physiology*; D034284:Dynamin I; D034281:Dynamins; D004705:Endocytosis / Q000502:physiology*; D020558:GTP Phosphohydrolases / Q000737:chemistry* / Q000378:metabolism*; D014644:Genetic Variation; D006801:Humans; D008961:Models, Structural; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D018408:Patch-Clamp Techniques; D010750:Phosphoproteins; D016133:Polymerase Chain Reaction; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D001798:Blood Proteins; D010750:Phosphoproteins; D011994:Recombinant Proteins; C039077:platelet protein P47; D034284:Dynamin I; D020558:GTP Phosphohydrolases; D034281:Dynamins