Rabs and cancer cell motility.
The Rab family of small GTPases functions in regulating vesicular transport in all eukaryotes. In the past few years, several important reports have linked some members of the Rab family to intriguing mechanistic aspects of cancer cell migration and invasiveness. Rab5 and Rab21 associate with alpha-integrin subunits and modulate their endosomal traffic and subcellular localization. Expression of the latter enhances adhesion and migration of certain cancer cell types. Rab25 has been functionally linked to tumor progression and the invasiveness of some epithelial cancers. Rab25 promotes invasive migration of cells in three-dimensional microenvironments by associating with alpha5beta1 integrin, and directing its recycling to dynamic ruffling protrusions at the migrating cell front. Acting directly, or through its effector, the Rab-coupling protein, Rab25 could potentially engage both integrin and epidermal growth factor receptor and enhance their oncogenic recycling and signaling. Tumor invasiveness may also be modulated by Rab8-mediated exocytic traffic of MT1-matrix metalloproteinase, with the latter's activity likely influenced by interaction with the mammalian suppressor of Sec4 (Mss4), a Rab8 guanine nucleotide exchange factor, and integrin. We discuss highlights in the recent literature that point towards a role for Rab-mediated membrane traffic in cancer cell migration and invasion.
Tang
Bor Luen
BL
Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore. bchtbl@nus.edu.sg
Ng
Ee Ling
EL
D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement; D004705:Endocytosis / Q000502:physiology; D066246:ErbB Receptors / Q000378:metabolism; D006801:Humans; D039081:Integrin alpha5beta1 / Q000378:metabolism; D053511:Matrix Metalloproteinase 14 / Q000378:metabolism; D009361:Neoplasm Invasiveness / Q000473:pathology; D009369:Neoplasms / Q000201:enzymology* / Q000473:pathology*; D022161:Transport Vesicles / Q000502:physiology*; D020691:rab GTP-Binding Proteins / Q000378:metabolism*
D039081:Integrin alpha5beta1; D066246:ErbB Receptors; D053511:Matrix Metalloproteinase 14; D020691:rab GTP-Binding Proteins