The rod cGMP phosphodiesterase delta subunit dissociates the small GTPase Rab13 from membranes.
Small Rab GTPases are involved in the regulation of membrane trafficking. They cycle between cytosolic and membrane-bound forms. These membrane association/dissociation are tightly controlled by regulatory proteins. To search for proteins interacting with Rab13, a small GTPase associated with vesicles in fibroblasts and predominantly with tight junctions in epithelial cells, we screened a HeLa two-hybrid cDNA library and isolated a clone encoding a protein of 17.4 kDa. This protein, almost identical to the bovine rod cGMP phosphodiesterase delta subunit, was named human delta-PDE. The delta-PDE binds specifically to Rab13. It exhibits two putative C-terminal sequences necessary for the interaction with PDZ (PSD95, Dlg, ZO-1) domains contained in many proteins localized to specific plasma membrane microdomains. Immunofluorescence microscopic studies revealed that the vesicular stomatitis virus (VSV)-tagged delta-PDE is localized in vesicular structures accumulated near the plasma membrane in epithelial cells. Deletion of the PDZ binding motifs impair VSV-delta-PDE subcellular distribution. Purified recombinant delta-PDE had the capacity to dissociate Rab13 from cellular membranes. Our data support the proposal that delta-PDE, but not GDP dissociation inhibitor, may serve to control the dynamic of the association of Rab13 with cellular membranes.
Marzesco
A M
AM
CNRS UMR 144, Compartimentation et Dynamique Cellulaires, Institut Curie, 75248 Paris Cedex 05, France.
Galli
T
T
Louvard
D
D
Zahraoui
A
A
D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000201:enzymology; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D018374:LLC-PK1 Cells; D008562:Membrane Glycoproteins; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D017948:Retinal Rod Photoreceptor Cells / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000201:enzymology; D013552:Swine; D014759:Viral Envelope Proteins / Q000378:metabolism; D020691:rab GTP-Binding Proteins
C028391:G protein, vesicular stomatitis virus; D008562:Membrane Glycoproteins; D014759:Viral Envelope Proteins; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; C085485:RAB13 protein, human; D020691:rab GTP-Binding Proteins