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Arabidopsis μ-adaptin subunit AP1M of adaptor protein complex 1 mediates late secretory and vacuolar traffic and is required for growth
- Source :
- Proceedings of the National Academy of Sciences. 110:10318-10323
- Publication Year :
- 2013
- Publisher :
- Proceedings of the National Academy of Sciences, 2013.
-
Abstract
- Adaptor protein (AP) complexes are the predominant coat proteins of membrane vesicles in post-Golgi trafficking of mammalian cells. Each AP complex contains a specific medium subunit, μ-adaptin, that selects cargo proteins bearing sequence-specific sorting motifs. Much less is known about the AP complexes and their μ subunits in plants. Because of uncertain homology, the μ-adaptins of Arabidopsis have been designated muA through muD [Happel et al. (2004) Plant J 37(5):678–693]. Furthermore, only muD has been assigned to a specific AP complex, AP-3, involved in Golgi-vacuolar trafficking [Niihama et al. (2009) Plant Cell Physiol 50(12):2057–2068, Zwiewka et al. (2011) Cell Res 21(12):1711–1722, and Wolfenstetter et al. (2012) Plant Cell 24(1):215–232]. In contrast, the μ subunit of neither the post-Golgi trafficking AP-1 complex nor the endocytic AP-2 complex has been identified. Here, we report the functional analysis of redundant AP-1 μ-adaptins AP1M1 (also known as muB1) and AP1M2 (also known as muB2). Coimmunoprecipitation revealed that both AP1M2 and its less strongly expressed isoform AP1M1 are complexed with the large subunit γ-adaptin of AP-1. In addition, AP1M2 was localized at or near the trans -Golgi network. Knockout mutations of AP1M2 impaired pollen function and arrested plant growth whereas the ap1m1 ap1m2 double mutant was nearly pollen-lethal. At the cellular level, the absence of AP1M2 entailed inhibition of multiple trafficking pathways from the trans -Golgi network to the vacuole and to the plasma membrane in interphase and to the plane of cell division in cytokinesis. Thus, AP-1 is crucial in post-Golgi trafficking in plant cells and required for cell division and plant growth.
- Subjects :
- Cell division
Protein subunit
Adaptor Protein Complex 1
Arabidopsis
Golgi Apparatus
Biology
Adaptor Protein Complex alpha Subunits
Microscopy, Electron, Transmission
Adaptor Protein Complex gamma Subunits
Interphase
Secretory pathway
Cytokinesis
Multidisciplinary
Arabidopsis Proteins
Secretory Vesicles
Cell Membrane
Signal transducing adaptor protein
Biological Sciences
Adaptor Protein Complex mu Subunits
Cell biology
Mutagenesis, Insertional
Protein Transport
Vacuoles
trans-Golgi Network
Subjects
Details
- ISSN :
- 10916490 and 00278424
- Volume :
- 110
- Database :
- OpenAIRE
- Journal :
- Proceedings of the National Academy of Sciences
- Accession number :
- edsair.doi.dedup.....0f779c99567162b2dca09c7599f3690c