Disease relevance of BAK1

• The two-domain Arabidopsis thaliana Str1 protein (At1g79230) was expressed in Escherichia coli as a mature protein, as a variant without the elongated linker sequence, and as AtStr1C332S and AtStr1C339V [1].

High impact information on BAK1

• BAK1, an Arabidopsis LRR receptor-like protein kinase, interacts with BRI1 and modulates brassinosteroid signaling [2].
• BAK1 and BRI1 share similar gene expression and subcellular localization patterns and physically associate with each other in plants [3].
• We propose that BAK1 and BRI1 function together to mediate plant steroid signaling [3].
• Overexpression of BAK1 results in elongated organ phenotypes, while a null allele of BAK1 displays a semidwarfed phenotype and has reduced sensitivity to brassinosteroids (BRs) [2].
• Mutations in GTE6 disrupt the formation of elliptical leaf laminae in mature leaves, whereas overexpression of GTE6 resulted in elongated juvenile leaves [4].

Biological context of BAK1

• Expression of a dominant-negative mutant allele of BAK1 causes a severe dwarf phenotype, resembling the phenotype of null bri1 alleles [2].
• Heterodimerization and endocytosis of Arabidopsis brassinosteroid receptors BRI1 and AtSERK3 (BAK1) [5].
• Brassinosteroids (BRs) regulate multiple aspects of plant growth and development and require an active BRASSINOSTEROID-INSENSITIVE1 (BRI1) and BRI1-ASSOCIATED RECEPTOR KINASE1 (BAK1) for hormone perception and signal transduction [6].
• A brassinosteroid-hypersensitive mutant of BAK1 indicates that a convergence of photomorphogenic and hormonal signaling modulates phototropism [7].
• In Arabidopsis thaliana brassinosteroid (BR), perception is mediated by two Leu-rich repeat receptor-like kinases, BRASSINOSTEROID INSENSITIVE1 (BRI1) and BRI1-ASSOCIATED RECEPTOR KINASE1 (BAK1) (Arabidopsis SOMATIC EMBRYOGENESIS RECEPTOR-like KINASE3 [AtSERK3]) [5].

Anatomical context of BAK1

• Using transient expression in protoplasts of BRI1 and AtSERK3 fused to cyan and yellow fluorescent green fluorescent protein variants allowed us to localize each receptor independently in vivo [5].
• Endocytic vesicles contain either BRI1 or AtSERK3 alone or both [5].
• Synthesis might start by making lipoglucans, which, in turn, might form the substrate for the endo-1,4-beta-glucanase, before being elongated to form the long, crystalline microfibrils that assemble in the cell wall [8].
• The strict arrangement in grana and stroma lamellae was lost, and instead a network of elongated and distorted grana was observed [9].
• Those peroxisomes bearing myc-AtPex11a, but not myc-AtPex11e, elongated prior to duplication [10].

Associations of BAK1 with chemical compounds

• BAK1 is a serine/threonine protein kinase, and BRI1 and BAK1 interact in vitro and in vivo [2].
• In the absence of auxin, cells elongated with concomitant increase in their ploidy level, but both were strongly inhibited by E2FB [11].
• Among its substrates is the basic domain/leucine zipper (bZIP) transcription factor ELONGATED HYPOCOTYL5 (HY5), one of the key regulators of photomorphogenesis under all light qualities, including UV-B responses required for tolerance to this environmental threat [12].
• We also tested the hypothesis that branches of amylopectin might serve as the primers for granule-bound starch synthase I. In this model, elongated branches of amylopectin are subsequently cleaved to form amylose [13].
• The activation tagging of YUCCA5 conferred increased levels of free indole acetic acid, increased auxin response, and mild phenotypic characteristics of auxin overproducers, such as elongated hypocotyls, epinastic cotyledons, and narrow leaves [14].

Regulatory relationships of BAK1

• It is believed that BRI1 becomes activated through heterodimerization with BAK1, a similar LRR receptor kinase, in response to BR signal [15].

Other interactions of BAK1

• Collectively, these results suggest that apart from SERK3, SERK1 is also involved in the brassinolide signaling pathway [16].
• Overexpression of the TTL gene results in a phenotype that was observed in weak bri1 mutants and null bak1 mutants [15].
• The sgr2 mutants also had misshapen seed and seedlings, whereas the stem of the zig/sgr4 mutants elongated in a zigzag fashion [17].
• Here, we show that arc11, one of 12 recessive accumulation and replication of chloroplasts (arc) mutants in Arabidopsis, contains highly elongated and multiple-arrayed chloroplasts in developing green tissues [18].
• Like phyB mutants, elf3 mutants have elongated hypocotyls and petioles, flower early, and have defects in the red light response [19].
• We report that BAK1-LIKE 1 (BKK1) functions redundantly with BAK1 in regulating BR signaling [20].

Analytical, diagnostic and therapeutic context of BAK1

• The abaxial surface of ant petals contains features such as stomata and elongated, interdigitated cells that are not present on wild-type petals [21].
• In physiological buffer, the circular dichroism spectra of the full-length dehydrins reveal overall disordered structures with a variable content of poly-Pro helices, a type of elongated secondary structure relying on bridging water molecules [22].
• Two of the triple-mutant lines, designated 55H and 70F, had elongated hypocotyls and fruit trusses, and pale immature fruits [23].

References