Rab11b resides in a vesicular compartment distinct from Rab11a in parietal cells and other epithelial cells.
The Rab11 family of small GTPases is composed of three members, Rab11a, Rab11b, and Rab25. While recent work on Rab11a and Rab25 has yielded some insights into their function, Rab11b has received little attention. Therefore, we sought to examine the distribution of endogenous Rab11b in epithelial cells. In rabbit gastric parietal cells, unlike Rab11a, Rab11b did not colocalize or coisolate with H(+)/K(+)-ATPase. In MDCK cells, endogenous Rab11b localized to an apical pericentrisomal region distinct from Rab11a. The microtubule agents nocodazole and taxol dramatically alter Rab11a's localization in the cell, while effects on Rab11b's distribution were less apparent. These results indicate that in contrast to Rab11a, the Rab11b compartment in the apical region is not as dependent upon microtubules. While Rab11a is known to regulate transferrin trafficking in nonpolarized cells and IgA trafficking in polarized cells, Rab11b exhibited little colocalization with either of these cargoes. Thus, while Rab11a and Rab11b share high sequence homology, they appear to reside within distinct vesicle compartments.
Department of Medicine, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA 30912, USA. lynne.lapierre@vanderbilt.edu
Lynne A
LA
Lapierre
Matthew C
MC
Dorn
C Faith
CF
Zimmerman
Jennifer
J
Navarre
Jason O
JO
Burnette
James R
JR
Goldenring
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D002451:Cell Compartmentation; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity; D004285:Dogs; D004847:Epithelial Cells / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D017506:H(+)-K(+)-Exchanging ATPase / Q000378:metabolism; D006801:Humans; D007070:Immunoglobulin A / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D051379:Mice; D015739:Nocodazole / Q000494:pharmacology; D017239:Paclitaxel / Q000494:pharmacology; D010295:Parietal Cells, Gastric / Q000378:metabolism*; D021381:Protein Transport; D011817:Rabbits; D011961:Receptors, Fc / Q000378:metabolism; D011990:Receptors, Transferrin / Q000378:metabolism; D014168:Transferrin / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000276:immunology / Q000378:metabolism*; D000099193:rab11 GTP-Binding Proteins
D000970:Antineoplastic Agents; D049452:Green Fluorescent Proteins; D017506:H(+)-K(+)-Exchanging ATPase; D007070:Immunoglobulin A; D008164:Luminescent Proteins; D015739:Nocodazole; D017239:Paclitaxel; D011961:Receptors, Fc; D011990:Receptors, Transferrin; D014168:Transferrin; D020691:rab GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins; C045281:IgA receptor