Vesicular transport and kidney development.
Vesicular transport processes play crucial roles in the biogenesis of cellular membranes and in the polarized transport functions of epithelial cells. During the 1990's we have witnessed major progress in elucidation of the machineries responsible for the intracellular membrane trafficking. The components of these machineries are abundant in tissues with a high content of epithelial cells, such as the kidney. However, the developmental role of the membrane trafficking apparatus in higher eukaryotes has been addressed hardly at all. We summarize here data on the presence and the functional role of vesicle transport proteins in the kidney, and describe work addressing the developmentally regulated expression and localization of three molecules suggested to be involved in polarized trafficking in kidney epithelia, Rab17, syntaxin 3, and Munc-18-2. The results show that specialized transport machinery is induced during differentiation of renal epithelia. However, the expression levels of the components under study are highest in the mature structures, indicating that the proteins are predominantly required for the function of mature epithelia and possibly for the maintenance of the polarized phenotype of specific epithelial cells. The proteins are, however, detected at low levels already in earlier, differentiating structures, and could thus also be involved in the differentiation of kidney epithelia.
Lehtonen
S
S
Department of Pathology, Haartman Institute, University of Helsinki, Finland.
Lehtonen
E
E
Olkkonen
V M
VM
D000818:Animals; D001693:Biological Transport, Active / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D018699:Coated Vesicles / Q000378:metabolism / Q000502:physiology*; D004627:Embryonic Induction; D007668:Kidney / Q000196:embryology* / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D051938:Munc18 Proteins; D009419:Nerve Tissue Proteins; D011506:Proteins / Q000378:metabolism; D050765:Qa-SNARE Proteins; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins / Q000378:metabolism
D008565:Membrane Proteins; D051938:Munc18 Proteins; D009419:Nerve Tissue Proteins; D011506:Proteins; D050765:Qa-SNARE Proteins; C497941:Stxbp2 protein, mouse; D033921:Vesicular Transport Proteins; C081073:rab17 protein, epithelial; D020691:rab GTP-Binding Proteins