#bri1 ems suppressor

[whats-in-a-sentence]

This results in activation of the transcription factors BRI1-EMS SUPPRESSOR1 (BESI1) and BRASSINAZOLE-RESISTANT1 (BZR1) and subsequent gene expression (Figure 15.31). The BRI1 receptor belongs to the plasma membrane leucine rich repeat (LRR) subfamily of RLKs and contains an N-terminal extracellular domain that binds brassinolide, a single transmembrane domain, and a cytoplasmic kinase domain with specificity toward tyrosine, serine, or threonine residues (see Figure 15.31). Upon binding brassinolide, homodimers of BRI1 are activated and heterooligomerize with the RLK BRI1-ASSOCIATED RECEPTOR KINASE1 (BAK1) (see Figure 15.31); both RLKs undergo auto- and transphosphorylation during activation. (...) In the presence of brassinolide, the activated phosphatase BSU1 dephosphorylates BIN2 and promotes its degradation by the 26S proteasome system, thus blocking its activity (see steps 6 and 7 in Figure 15.31). (...) Similarly, brassinosteroid binding to the receptor kinase BRI1 causes the repressor protein BIN2 to become inactivated, resulting in activation of the transcription factors BES1 and BZR1 (see Figure 15.31). (...) As noted above, protein dephosphorylation is employed by the brassinosteroid pathway to inactivate the repressor protein BIN2 (see Figure 15.31).

"Plant Physiology and Development" int'l 6e - Taiz, L., Zeiger, E., Møller, I.M., Murphy, A.

[tenth-sentence]

BES1 and BZR1 are then dephosphorylated by PROTEIN PHOSPHATASE2A (PP2A), and the active forms of BES1 and BZR1 move into the nucleus where they regulate the expression of brassinolide response genes (see Figure 15.31).

"Plant Physiology and Development" int'l 6e - Taiz, L., Zeiger, E., Møller, I.M., Murphy, A.