Kinesin-2 mediates apical endosome transport during epithelial lumen formation

Abstract

Apical lumen formation is a key step during epithelial morphogenesis of tubular organs. Appropriate transport and targeting of apical proteins to the apical membrane initiation site (AMIS) plays a crucial role in establishing a solitary, central lumen. FIP5, a Rab11-interacting protein, is an important regulator that directs apical endosome trafficking along microtubules toward the AMIS during cytokinesis. However, it is unknown which molecular motor(s) transports FIP5-positive apical endosomes during lumen initiation, and how this process is regulated. In this study, we demonstrate that the interaction of FIP5 with the microtubule motor, Kinesin-2, is required for the movement of FIP5-endosomes and delivery of these endosomes from centrosomes to the cleavage furrow during apical lumen initiation. Loss of Kinesin-2 disrupts targeting of apical proteins to the AMIS and results in multiple lumen formation in MDCK cysts. Our data provide more details to the molecular mechanism of FIP5-dependent apical trafficking during apical lumen formation.

Rab GTPases and cell division

“…In a recent study, it was shown that the AMIS forms around the midbody during late telophase and that Rab11 effector protein FIP5, and endosomes containing apical proteins associated with it, are all transported to the AMIS along central spindle microtubules. 41 Then, these FIP5-endosomes fuse with the plasma membrane at the cleavage furrow neighboring the AMIS, thus supplying apical components (Crumbs-3a and glycoprotein135 (gp135)) needed for the formation and progression of the emerging lumen (Fig. 2).…”

“…Additionally, it was demonstrated that Kinesin-2 molecular motor directly binds to FIP5, thus mediating the delivery of FIP5-endosomes to the AMIS along central spindle microtubules during telophase. 41 FIP5 also binds sorting nexin 18 (SNX18). In particular, this interaction is needed for apical endocytic carrier formation and lumen formation.…”

“…Surprisingly, it was shown that Kinesin-2 and SNX18 compete for binding to FIP5. In summary, it was proposed that FIP5 may interact with SNX18 and Kinesin-2 in hand-me-down fashion, thus mediating sequential steps of endocytic carrier formation and transport during lumen initiation at late telophase 41 (Fig. 2).…”

Proteomics Screen Identifies Class I Rab11 Family Interacting Proteins as Key Regulators of Cytokinesis

“…Interestingly, kinesin-2 was shown to be involved in the delivery of Rab11-FIP5 to the cleavage furrow of epithelial cells (43), but whether Rip11 associates with kinesin-2 or another motor protein is currently unknown. Alternatively, 14-3-3 might regulate the C2 domain of Rip11 and its capacity to bind phospholipids, but more work will be required to assess these possibilities.…”

3D Time-Lapse Analysis of Rab11/FIP5 Complex: Spatiotemporal Dynamics During Apical Lumen Formation

“…We have created a protocol for 3D-time-lapse analysis of apical lumen formation using Madin-Darby canine kidney (MDCK) cells [3, 9]. Using this technique we were able to determine that cingulin is one of the first proteins recruited to the AMIS during late telophase, and that the Rab11/FIP5-endosomes are transported after AMIS formation around the midbody [3].…”