Rab GTPase family 11 (Rab11)-like includes Rab11a, Rab11b, and Rab25
Rab11a, Rab11b, and Rab25 are closely related, evolutionary conserved Rab proteins that are differentially expressed. Rab11a is ubiquitously synthesized, Rab11b is enriched in brain and heart and Rab25 is only found in epithelia. Rab11/25 proteins seem to regulate recycling pathways from endosomes to the plasma membrane and to the trans-Golgi network. Furthermore, Rab11a is thought to function in the histamine-induced fusion of tubulovesicles containing H+, K+ ATPase with the plasma membrane in gastric parietal cells and in insulin-stimulated insertion of GLUT4 in the plasma membrane of cardiomyocytes. Overexpression of Rab25 has recently been observed in ovarian cancer and breast cancer, and has been correlated with worsened outcomes in both diseases. In addition, Rab25 overexpression has also been observed in prostate cancer, transitional cell carcinoma of the bladder, and invasive breast tumor cells. GTPase activating proteins (GAPs) interact with GTP-bound Rab and accelerate the hydrolysis of GTP to GDP. Guanine nucleotide exchange factors (GEFs) interact with GDP-bound Rabs to promote the formation of the GTP-bound state. Rabs are further regulated by guanine nucleotide dissociation inhibitors (GDIs), which facilitate Rab recycling by masking C-terminal lipid binding and promoting cytosolic localization. Most Rab GTPases contain a lipid modification site at the C-terminus, with sequence motifs CC, CXC, or CCX. Lipid binding is essential for membrane attachment, a key feature of most Rab proteins. Due to the presence of truncated sequences in this CD, the lipid modification site is not available for annotation.