Bridging integrator 2 (BIN2) promotes cell motility and migration, probably via its interaction with the cell membrane and with podosome proteins that mediate interaction with the cytoskeleton []. It contains a BAR domain that mediates dimerisation and interaction with membranes enriched in phosphatidylinositides [].
This domain is found in plant proteins, many of which also contain an F-box domain []. This domain can be found in KIB3 from Arabidopsis. KIB3 is a F-box E3 ubiquitin ligase that promotes the degradation of GSK3-like kinase BIN2 while blocking its substrate access [].
This family consists of several plant proteins, including protein OCTOPUS (OPS, At3g09070) and OPSL1 (At5g01170) from Arabidopsis []. OPS is a membrane-associated protein that regulates phloem differentiation entry []. It is a positive regulator of the brassinosteroid (BR) signaling pathway and sequesters BIN2 to the plasma membrane to promote phloem differentiation [].
This entry represents a group of plant bHLH transcription factors, including FAMA, SPEECHLESS and MUTE from Arabidopsis. These proteins have been shown to play important parts in stomatal lineage development. SPEECHLESS (SPCH) generates stem cells and promotes their asymmetric division while MUTE regulates the meristemoid to Guard Mother Cell (GMC) transition. FAMA confers guard cell (GC) fate and is expressed at the equal division producing the two young GCs, but not in mature stomata [, ].SPCH can be regulated through phosphorylation by MAPK-mediated and BIN2 (BR INSENSITIVE2). It has been suggested that SPCH integrates brassinosteroid and stomata signalling pathways [].
