Structural highlights
Function
RAB8A_HUMAN May be involved in vesicular trafficking and neurotransmitter release. Together with RAB11A, RAB3IP, the exocyst complex, PARD3, PRKCI, ANXA2, CDC42 and DNMBP promotes transcytosis of PODXL to the apical membrane initiation sites (AMIS), apical surface formation and lumenogenesis. Together with MYO5B and RAB11A participates in epithelial cell polarization.[1] [2]
Publication Abstract from PubMed
EHBP1 is an adaptor protein that regulates vesicular trafficking by recruiting Rab8 family members and Eps15-homology domain-containing proteins 1/2 (EHD1/2). It also links endosomes to the actin cytoskeleton. However, the underlying molecular mechanism of activation of EHBP1 actin-binding activity is unclear. Here, we show that both termini of EHBP1 have membrane targeting potential. EHBP1 associates with PI(3)P, PI(5)P, and phosphatidylserine via its N-terminal C2 domain. We show that in the absence of Rab8 family members, the C-terminal bivalent Mical/EHBP Rab binding (bMERB) domain forms an intramolecular complex with its central calponin homology (CH) domain and auto-inhibits actin binding. Rab8 binding to the bMERB domain relieves this inhibition. We have analyzed the CH:bMERB auto-inhibited complex and the active bMERB:Rab8 complex biochemically and structurally. Together with structure-based mutational studies, this explains how binding of Rab8 frees the CH domain and allows it to interact with the actin cytoskeleton, leading to membrane tubulation.
The mechanism of activation of the actin binding protein EHBP1 by Rab8 family members.,Rai A, Bleimling N, Vetter IR, Goody RS Nat Commun. 2020 Aug 21;11(1):4187. doi: 10.1038/s41467-020-17792-3. PMID:32826901[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Bryant DM, Datta A, Rodriguez-Fraticelli AE, Peranen J, Martin-Belmonte F, Mostov KE. A molecular network for de novo generation of the apical surface and lumen. Nat Cell Biol. 2010 Nov;12(11):1035-45. doi: 10.1038/ncb2106. Epub 2010 Oct 3. PMID:20890297 doi:10.1038/ncb2106
- ↑ Roland JT, Bryant DM, Datta A, Itzen A, Mostov KE, Goldenring JR. Rab GTPase-Myo5B complexes control membrane recycling and epithelial polarization. Proc Natl Acad Sci U S A. 2011 Feb 15;108(7):2789-94. doi:, 10.1073/pnas.1010754108. Epub 2011 Jan 31. PMID:21282656 doi:10.1073/pnas.1010754108
- ↑ Rai A, Bleimling N, Vetter IR, Goody RS. The mechanism of activation of the actin binding protein EHBP1 by Rab8 family members. Nat Commun. 2020 Aug 21;11(1):4187. PMID:32826901 doi:10.1038/s41467-020-17792-3
