Rab11-FIP1A regulates early trafficking into the recycling endosomes.
Jenny C Schafer, Rebecca E McRae, Elizabeth H Manning, Lynne A Lapierre, James R Goldenring
Author Information
Jenny C Schafer: Departments of Surgery, Nashville, TN, USA; Epithelial Biology Center, Nashville, TN, USA.
Rebecca E McRae: Departments of Surgery, Nashville, TN, USA; Cell & Developmental Biology, Nashville, TN, USA; Epithelial Biology Center, Nashville, TN, USA.
Elizabeth H Manning: Departments of Surgery, Nashville, TN, USA; Epithelial Biology Center, Nashville, TN, USA.
Lynne A Lapierre: Departments of Surgery, Nashville, TN, USA; Epithelial Biology Center, Nashville, TN, USA.
James R Goldenring: Departments of Surgery, Nashville, TN, USA; Cell & Developmental Biology, Nashville, TN, USA; Epithelial Biology Center, Nashville, TN, USA; Vanderbilt University School of Medicine and the Nashville VA Medical Center, Nashville, TN, USA. Electronic address: jim.goldenring@vanderbilt.edu.
The Rab11 family of small GTPases, along with the Rab11-family interacting proteins (Rab11-FIPs), are critical regulators of intracellular vesicle trafficking and recycling. We have identified a point mutation of Threonine-197 site to an Alanine in Rab11-FIP1A, which causes a dramatic dominant negative phenotype when expressed in HeLa cells. The normally perinuclear distribution of GFP-Rab11-FIP1A was condensed into a membranous cisternum with almost no GFP-Rab11-FIP1A(T197A) remaining outside of this central locus. Also, this condensed GFP-FIP1A(T197A) altered the distribution of proteins in the Rab11a recycling pathway including endogenous Rab11a, Rab11-FIP1C, and transferrin receptor (CD71). Furthermore, this condensed GFP-FIP1A(T197A)-containing structure exhibited little movement in live HeLa cells. Expression of GFP-FIP1A(T197A) caused a strong blockade of transferrin recycling. Treatment of cells expressing GFP-FIP1A(T197A) with nocodazole did not disperse the Rab11a-containing recycling system. We also found that Rab5 and EEA1 were accumulated in membranes by GFP-Rab11-FIP1A but Rab4 was unaffected, suggesting that a direct pathway may exist from early endosomes into the Rab11a-containing recycling system. Our study of a potent inhibitory trafficking mutation in Rab11-FIP1A shows that Rab11-FIP1A associates with and regulates trafficking at an early step in the process of membrane recycling.
