EHBP1L1 coordinates Rab8 and Bin1 to regulate apical-directed transport in polarized epithelial cells

Atsuhiro Nakajo; Shin-ichiro Yoshimura; Hiroko Togawa; Masataka Kunii; Tomohiko Iwano; Ayaka Izumi; Yuria Noguchi; Ayako Watanabe; Ayako Goto; Toshiro Sato; Akihiro Harada

doi:10.1083/jcb.201508086

EHBP1L1 coordinates Rab8 and Bin1 to regulate apical-directed transport in polarized epithelial cells

J Cell Biol. 2016 Feb 1;212(3):297-306. doi: 10.1083/jcb.201508086.

Affiliations

¹ Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.
² Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan shyoshimura@acb.med.osaka-u.ac.jp aharada@acb.med.osaka-u.ac.jp.
³ Department of Gastroenterology, Keio University School of Medicine, Tokyo 160-8582, Japan.

Abstract

The highly conserved Rab guanosine triphosphatase (GTPase) Rab8 plays a role in exocytosis toward the polarized plasma membrane in eukaryotic cells. In murine Rab8-deficient small intestine cells, apical proteins are missorted into lysosomes. In this study, we identified a novel Rab8-interacting protein complex containing an EH domain-binding protein 1-like 1 (EHBP1L1), Bin1/amphiphysin II, and dynamin. Biochemical analyses showed that EHBP1L1 directly bound to GTP-loaded Rab8 and Bin1. The spatial dependency of these complexes at the endocytic recycling compartment (ERC) was demonstrated through overexpression and knockdown experiments. EHBP1L1- or Bin1-depleted or dynamin-inhibited small intestine organoids significantly accumulated apical membrane proteins but not basolateral membrane proteins in lysosomes. Furthermore, in EHBP1L1-deficient mice, small intestine cells displayed truncated and sparse microvilli, suggesting that EHBP1L1 maintains the apical plasma membrane by regulating apical transport. In summary, our data demonstrate that EHBP1L1 links Rab8 and the Bin1-dynamin complex, which generates membrane curvature and excises the vesicle at the ERC for apical transport.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adaptor Proteins, Signal Transducing / genetics
Adaptor Proteins, Signal Transducing / metabolism*
Animals
Biological Transport
Carrier Proteins / genetics
Carrier Proteins / metabolism*
Cell Polarity*
Dynamins / metabolism
Epithelial Cells / enzymology*
Epithelial Cells / ultrastructure
HEK293 Cells
HeLa Cells
Humans
Intestinal Mucosa / enzymology*
Intestinal Mucosa / ultrastructure
Intestine, Small / enzymology*
Intestine, Small / ultrastructure
Lysosomes / enzymology
Mice
Mice, Knockout
Microvilli / enzymology
Nerve Tissue Proteins / genetics
Nerve Tissue Proteins / metabolism*
Nuclear Proteins / genetics
Nuclear Proteins / metabolism*
Organoids
Protein Binding
Protein Interaction Domains and Motifs
Protein Transport
RNA Interference
Signal Transduction
Transfection
Transport Vesicles / enzymology*
Tumor Suppressor Proteins / genetics
Tumor Suppressor Proteins / metabolism*
rab GTP-Binding Proteins / genetics
rab GTP-Binding Proteins / metabolism*

Substances

Adaptor Proteins, Signal Transducing
BIN1 protein, human
Bin1 protein, mouse
Carrier Proteins
EHBP1L1 protein, human
EHBP1L1 protein, mouse
Nerve Tissue Proteins
Nuclear Proteins
Rab8 protein, mouse
Tumor Suppressor Proteins
RAB8A protein, human
rab GTP-Binding Proteins
Dynamins

Associated data

RefSeq/NP_001108067