| Structural highlights
Function
ACAP1_HUMAN GTPase-activating protein (GAP) for ADP ribosylation factor 6 (ARF6) required for clathrin-dependent export of proteins from recycling endosomes to trans-Golgi network and cell surface. Required for regulated export of ITGB1 from recycling endosomes to the cell surface and ITGB1-dependent cell migration.[1] [2] [3] [4] [5]
Publication Abstract from PubMed
The BAR (Bin-Amphiphysin-Rvs) domain undergoes dimerization to produce a curved protein structure, which superimposes onto membrane through electrostatic interactions to sense and impart membrane curvature. In some cases, a BAR domain also possesses an amphipathic helix that inserts into the membrane to induce curvature. ACAP1 (Arfgap with Coil coil, Ankyrin repeat, and PH domain protein 1) contains a BAR domain. Here, we show that this BAR domain can neither bind membrane nor impart curvature, but instead requires a neighboring PH (Pleckstrin Homology) domain to achieve these functions. Specific residues within the PH domain are responsible for both membrane binding and curvature generation. The BAR domain adjacent to the PH domain instead interacts with the BAR domains of neighboring ACAP1 proteins to enable clustering at the membrane. Thus, we have uncovered the molecular basis for an unexpected and unconventional collaboration between PH and BAR domains in membrane bending.
A PH Domain in ACAP1 Possesses Key Features of the BAR Domain in Promoting Membrane Curvature.,Pang X, Fan J, Zhang Y, Zhang K, Gao B, Ma J, Li J, Deng Y, Zhou Q, Egelman EH, Hsu VW, Sun F Dev Cell. 2014 Oct 13;31(1):73-86. doi: 10.1016/j.devcel.2014.08.020. Epub 2014, Oct 2. PMID:25284369[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Jackson TR, Brown FD, Nie Z, Miura K, Foroni L, Sun J, Hsu VW, Donaldson JG, Randazzo PA. ACAPs are arf6 GTPase-activating proteins that function in the cell periphery. J Cell Biol. 2000 Oct 30;151(3):627-38. PMID:11062263
- ↑ Li J, Ballif BA, Powelka AM, Dai J, Gygi SP, Hsu VW. Phosphorylation of ACAP1 by Akt regulates the stimulation-dependent recycling of integrin beta1 to control cell migration. Dev Cell. 2005 Nov;9(5):663-73. PMID:16256741 doi:http://dx.doi.org/S1534-5807(05)00374-6
- ↑ Ma Z, Nie Z, Luo R, Casanova JE, Ravichandran KS. Regulation of Arf6 and ACAP1 signaling by the PTB-domain-containing adaptor protein GULP. Curr Biol. 2007 Apr 17;17(8):722-7. Epub 2007 Mar 29. PMID:17398097 doi:http://dx.doi.org/S0960-9822(07)01115-3
- ↑ Li J, Peters PJ, Bai M, Dai J, Bos E, Kirchhausen T, Kandror KV, Hsu VW. An ACAP1-containing clathrin coat complex for endocytic recycling. J Cell Biol. 2007 Jul 30;178(3):453-64. PMID:17664335 doi:http://dx.doi.org/jcb.200608033
- ↑ Bai M, Pang X, Lou J, Zhou Q, Zhang K, Ma J, Li J, Sun F, Hsu V. Mechanistic insights into regulated cargo binding by ACAP1. J Biol Chem. 2012 May 29. PMID:22645133 doi:10.1074/jbc.M112.378810
- ↑ Pang X, Fan J, Zhang Y, Zhang K, Gao B, Ma J, Li J, Deng Y, Zhou Q, Egelman EH, Hsu VW, Sun F. A PH Domain in ACAP1 Possesses Key Features of the BAR Domain in Promoting Membrane Curvature. Dev Cell. 2014 Oct 13;31(1):73-86. doi: 10.1016/j.devcel.2014.08.020. Epub 2014, Oct 2. PMID:25284369 doi:http://dx.doi.org/10.1016/j.devcel.2014.08.020
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