Class I Rab11-family interacting proteins are binding targets for the Rab14 GTPase.
BACKGROUND
Rab11 and Rab14 are two related Rab GTPases that are believed to function in endosomal recycling and Golgi/endosome transport processes. We, and others, have identified a group of proteins that interact with Rab11 and function as Rab11 effectors, known as the Rab11-FIPs (family interacting proteins). This protein family has been sub-classified into two groups - class I FIPs [FIP2, RCP (Rab coupling protein) and Rip11 (Rab11-interacting protein)] and class II FIPs (FIP3 and FIP4).


RESULTS
In the present study we identify the class I FIPs as dual Rab-binding proteins by demonstrating that they also interact with Rab14 in a GTP-dependent manner. We show that these interactions are specific for the class I FIPs and that they occur via their C-terminal regions, which encompass the previously described RBD (Rab11-binding domain). Furthermore, we show that Rab14 significantly co-localizes with the TfnR (transferrin receptor) and that Rab14 Q70L co-localizes with Rab11a and with the class I FIPs on the ERC (endosomal recycling compartment) during interphase. Additionally, we show that during cytokinesis Rab14 localizes to the cleavage furrow/midbody.


CONCLUSIONS
The data presented in the present study, which identifies the class I FIPs as the first putative effector proteins for the Rab14 GTPase, indicates greater complexity in the Rab-binding specificity of the class I FIP proteins.
Kelly
Eoin E
EE
Molecular Cell Biology Laboratory, Department of Biochemistry, Biosciences Institute, University College Cork, Cork, Ireland.
Horgan
Conor P
CP
Adams
Christine
C
Patzer
Tomasz M
TM
Ní Shúilleabháin
Deirdre M
DM
Norman
Jim C
JC
McCaffrey
Mary W
MW
D001665:Binding Sites; D002453:Cell Cycle / Q000502:physiology; D045744:Cell Line, Tumor; D011992:Endosomes / Q000378:metabolism; D005260:Female; D005455:Fluorescent Antibody Technique; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D011485:Protein Binding; D021381:Protein Transport / Q000502:physiology; D020691:rab GTP-Binding Proteins / Q000378:metabolism*; D000099193:rab11 GTP-Binding Proteins
D006160:Guanosine Triphosphate; D020691:rab GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins