Disease relevance of SYP111

• To explore the significance of this regulation, we expressed KNOLLE protein under the control of two constitutive promoters, the flower-specific AP3 and the cauliflower mosaic virus 35S promoter [1].

High impact information on SYP111

• Our results suggest a function for KN in cytokinesis [2].
• Mutations in the KNOLLE (KN) gene affect the rate and plane of cell divisions as well as cell morphology, resulting in mutant seedlings with a disturbed radial organization of tissue layers [2].
• During embryogenesis, KN transcripts are detected in patches of single cells or small cell groups [2].
• Analysis of the Arabidopsis genome revealed two further SNAP25-like proteins that also interacted with KN in the yeast two-hybrid assay [3].
• Here, we characterize AtSNAP33, an Arabidopsis homologue of the t-SNARE SNAP25, that was identified as a KN interactor in a yeast two-hybrid screen [3].

Biological context of SYP111

• AtSNAP33 is a ubiquitously expressed membrane-associated protein that accumulated at the plasma membrane and during cell division colocalized with KN at the forming cell plate [3].
• KNOLLE mRNA and protein expression is tightly regulated during the cell cycle [1].
• In contrast to KNOLLE, SYP31 resides in defined punctate membrane structures during interphase and is targeted during cytokinesis to the division plane [4].

Anatomical context of SYP111

• Here, we show that KN protein localisation is unaffected in keu mutant cells, which, like kn, display phragmoplast microtubules and accumulate ADL1 protein in the plane of cell division but vesicles fail to fuse with one another [5].
• The transgenic plants developed normally, although KNOLLE mRNA and protein accumulated to high levels in non-proliferating cells and protein was incorporated into membranes [1].

Physical interactions of SYP111

• More importantly, KEULE binds the cytokinesis-specific syntaxin KNOLLE [6].
• Consistent with the localization studies, NSPN11 was found to interact with KNOLLE [7].
• In contrast, we show that KNOLLE assembles in vitro into a large approximately 20S complex in an Sec18p/NSF-dependent manner [4].

Other interactions of SYP111

• NPSN11 is a cell plate-associated SNARE protein that interacts with the syntaxin KNOLLE [7].
• Genetic interactions between KN and KEU were analysed in double mutant embryos [5].
• By comparative in situ hybridisation to embryo sections, the 35S promoter yielded, relative to the endogenous KNOLLE promoter, low levels of KNOLLE mRNA accumulation in proliferating cells that were insufficient to rescue cytokinesis-defective knolle mutant embryos [1].
• The most well-characterized component, KNOLLE, a cell plate-specific soluble N-ethylmaleimide-sensitive fusion protein (NSF)-attachment protein receptor (SNARE), is a membrane fusion machine component required for plant cytokinesis [4].
• In vitro-binding studies demonstrate that AtCDC48 specifically interacts in an ATP-dependent manner with SYP31 but not with KNOLLE [4].

Analytical, diagnostic and therapeutic context of SYP111

• Using immunofluorescence microscopy, KNOLLE protein was found to be specifically expressed during mitosis and, unlike the plasma membrane H+-ATPase, to localize to the plane of division during cytokinesis [8].
• We have raised specific rabbit antiserum against purified recombinant KNOLLE protein to show biochemically and by immunoelectron microscopy that KNOLLE protein is membrane associated [8].

References