Toolkit/active phytochrome binding domain

active phytochrome binding domain

Protein Domain·Research·Since 2007

Also known as: APB domain

Taxonomy: Mechanism Branch / Component. Workflows sit above the mechanism and technique branches rather than replacing them.

Summary

The active phytochrome binding (APB) domain is a protein interaction module present in most phytochrome-interacting factors (PIFs) that mediates binding to light-activated phytochrome B (phyB). In Arabidopsis PIF4 and PIF5, this domain is required for phyB-associated, phosphorylation-preceded, proteasome-sensitive degradation in a light-regulated shade-avoidance pathway.

Usefulness & Problems

Why this is useful

The APB domain is useful as a light-responsive interaction element because it confers association with activated phyB and links that interaction to regulated protein turnover in specific PIF contexts. This makes it relevant for studying or engineering light-controlled transcriptional regulation and degradation processes tied to phytochrome signaling.

Problem solved

This domain helps solve the problem of coupling light perception by phyB to selective regulation of downstream transcription factors. The cited work specifically supports a role in mediating light-dependent control of PIF4 and PIF5 stability during shade-avoidance signaling.

Taxonomy & Function

Primary hierarchy

Mechanism Branch

Component: A low-level protein part used inside a larger architecture that realizes a mechanism.

Techniques

No technique tags yet.

Target processes

degradationtranscription

Input: Light

Implementation Constraints

The evidence indicates that the APB domain functions in the context of PIF proteins, where it mediates interaction with light-activated phyB. For PIF4 and PIF5, degradation is phosphorylation-associated and proteasome-sensitive, so implementations relying on turnover would depend on activated phyB and intact cellular degradation machinery; no construct architecture or expression-system optimization is described.

The supplied evidence is centered on Arabidopsis PIF4 and PIF5 in the shade-avoidance pathway and does not establish performance across diverse hosts, constructs, or synthetic applications. Quantitative properties such as binding affinity, kinetics, spectral parameters, and transferability as a standalone engineered module are not provided.

Validation

Cell-freeBacteriaMammalianMouseHumanTherapeuticIndep. Replication

Supporting Sources

Ranked Claims

Claim 1genetic interactionsupports2007Source 1needs review

The constitutive shade-avoidance phenotype of phyB mutants partially reverts in the absence of PIF4 and PIF5.

Consistent with this idea, the constitutive shade-avoidance phenotype of phyB mutants partially reverts in the absence of PIF4 and PIF5.
Claim 2genetic interactionsupports2007Source 1needs review

The constitutive shade-avoidance phenotype of phyB mutants partially reverts in the absence of PIF4 and PIF5.

Consistent with this idea, the constitutive shade-avoidance phenotype of phyB mutants partially reverts in the absence of PIF4 and PIF5.
Claim 3genetic interactionsupports2007Source 1needs review

The constitutive shade-avoidance phenotype of phyB mutants partially reverts in the absence of PIF4 and PIF5.

Consistent with this idea, the constitutive shade-avoidance phenotype of phyB mutants partially reverts in the absence of PIF4 and PIF5.
Claim 4genetic interactionsupports2007Source 1needs review

The constitutive shade-avoidance phenotype of phyB mutants partially reverts in the absence of PIF4 and PIF5.

Consistent with this idea, the constitutive shade-avoidance phenotype of phyB mutants partially reverts in the absence of PIF4 and PIF5.
Claim 5genetic interactionsupports2007Source 1needs review

The constitutive shade-avoidance phenotype of phyB mutants partially reverts in the absence of PIF4 and PIF5.

Consistent with this idea, the constitutive shade-avoidance phenotype of phyB mutants partially reverts in the absence of PIF4 and PIF5.
Claim 6genetic interactionsupports2007Source 1needs review

The constitutive shade-avoidance phenotype of phyB mutants partially reverts in the absence of PIF4 and PIF5.

Consistent with this idea, the constitutive shade-avoidance phenotype of phyB mutants partially reverts in the absence of PIF4 and PIF5.
Claim 7mechanistic modelsupports2007Source 1needs review

Shade avoidance in dense vegetation is triggered at least partially by reduced phytochrome-mediated degradation of transcription factors such as PIF4 and PIF5.

Our data suggest that, in dense vegetation, which is rich in far-red light, shade avoidance is triggered, at least partially, as a consequence of reduced phytochrome-mediated degradation of transcription factors such as PIF4 and PIF5.
Claim 8mechanistic modelsupports2007Source 1needs review

Shade avoidance in dense vegetation is triggered at least partially by reduced phytochrome-mediated degradation of transcription factors such as PIF4 and PIF5.

Our data suggest that, in dense vegetation, which is rich in far-red light, shade avoidance is triggered, at least partially, as a consequence of reduced phytochrome-mediated degradation of transcription factors such as PIF4 and PIF5.
Claim 9mechanistic modelsupports2007Source 1needs review

Shade avoidance in dense vegetation is triggered at least partially by reduced phytochrome-mediated degradation of transcription factors such as PIF4 and PIF5.

Our data suggest that, in dense vegetation, which is rich in far-red light, shade avoidance is triggered, at least partially, as a consequence of reduced phytochrome-mediated degradation of transcription factors such as PIF4 and PIF5.
Claim 10mechanistic modelsupports2007Source 1needs review

Shade avoidance in dense vegetation is triggered at least partially by reduced phytochrome-mediated degradation of transcription factors such as PIF4 and PIF5.

Our data suggest that, in dense vegetation, which is rich in far-red light, shade avoidance is triggered, at least partially, as a consequence of reduced phytochrome-mediated degradation of transcription factors such as PIF4 and PIF5.
Claim 11mechanistic modelsupports2007Source 1needs review

Shade avoidance in dense vegetation is triggered at least partially by reduced phytochrome-mediated degradation of transcription factors such as PIF4 and PIF5.

Our data suggest that, in dense vegetation, which is rich in far-red light, shade avoidance is triggered, at least partially, as a consequence of reduced phytochrome-mediated degradation of transcription factors such as PIF4 and PIF5.
Claim 12mechanistic modelsupports2007Source 1needs review

Shade avoidance in dense vegetation is triggered at least partially by reduced phytochrome-mediated degradation of transcription factors such as PIF4 and PIF5.

Our data suggest that, in dense vegetation, which is rich in far-red light, shade avoidance is triggered, at least partially, as a consequence of reduced phytochrome-mediated degradation of transcription factors such as PIF4 and PIF5.
Claim 13mechanistic requirementsupports2007Source 1needs review

Degradation of PIF4 and PIF5 is preceded by phosphorylation, requires the APB domain, and is sensitive to proteasome inhibitors, suggesting degradation upon interaction with light-activated phyB.

Degradation of these transcription factors is preceded by phosphorylation, requires the APB domain and is sensitive to inhibitors of the proteasome, suggesting that PIF4 and PIF5 are degraded upon interaction with light-activated phyB.
Claim 14mechanistic requirementsupports2007Source 1needs review

Degradation of PIF4 and PIF5 is preceded by phosphorylation, requires the APB domain, and is sensitive to proteasome inhibitors, suggesting degradation upon interaction with light-activated phyB.

Degradation of these transcription factors is preceded by phosphorylation, requires the APB domain and is sensitive to inhibitors of the proteasome, suggesting that PIF4 and PIF5 are degraded upon interaction with light-activated phyB.
Claim 15mechanistic requirementsupports2007Source 1needs review

Degradation of PIF4 and PIF5 is preceded by phosphorylation, requires the APB domain, and is sensitive to proteasome inhibitors, suggesting degradation upon interaction with light-activated phyB.

Degradation of these transcription factors is preceded by phosphorylation, requires the APB domain and is sensitive to inhibitors of the proteasome, suggesting that PIF4 and PIF5 are degraded upon interaction with light-activated phyB.
Claim 16mechanistic requirementsupports2007Source 1needs review

Degradation of PIF4 and PIF5 is preceded by phosphorylation, requires the APB domain, and is sensitive to proteasome inhibitors, suggesting degradation upon interaction with light-activated phyB.

Degradation of these transcription factors is preceded by phosphorylation, requires the APB domain and is sensitive to inhibitors of the proteasome, suggesting that PIF4 and PIF5 are degraded upon interaction with light-activated phyB.
Claim 17mechanistic requirementsupports2007Source 1needs review

Degradation of PIF4 and PIF5 is preceded by phosphorylation, requires the APB domain, and is sensitive to proteasome inhibitors, suggesting degradation upon interaction with light-activated phyB.

Degradation of these transcription factors is preceded by phosphorylation, requires the APB domain and is sensitive to inhibitors of the proteasome, suggesting that PIF4 and PIF5 are degraded upon interaction with light-activated phyB.
Claim 18mechanistic requirementsupports2007Source 1needs review

Degradation of PIF4 and PIF5 is preceded by phosphorylation, requires the APB domain, and is sensitive to proteasome inhibitors, suggesting degradation upon interaction with light-activated phyB.

Degradation of these transcription factors is preceded by phosphorylation, requires the APB domain and is sensitive to inhibitors of the proteasome, suggesting that PIF4 and PIF5 are degraded upon interaction with light-activated phyB.
Claim 19mechanistic requirementsupports2007Source 1needs review

Degradation of PIF4 and PIF5 is preceded by phosphorylation, requires the APB domain, and is sensitive to proteasome inhibitors, suggesting degradation upon interaction with light-activated phyB.

Degradation of these transcription factors is preceded by phosphorylation, requires the APB domain and is sensitive to inhibitors of the proteasome, suggesting that PIF4 and PIF5 are degraded upon interaction with light-activated phyB.

Approval Evidence

1 source1 linked approval claimfirst-pass slug active-phytochrome-binding-domain
most of the PIFs contain an active phytochrome binding (APB) domain that mediates their interaction with light-activated phytochrome B (phyB).

Source:

mechanistic requirementsupports

Degradation of PIF4 and PIF5 is preceded by phosphorylation, requires the APB domain, and is sensitive to proteasome inhibitors, suggesting degradation upon interaction with light-activated phyB.

Degradation of these transcription factors is preceded by phosphorylation, requires the APB domain and is sensitive to inhibitors of the proteasome, suggesting that PIF4 and PIF5 are degraded upon interaction with light-activated phyB.

Source:

Comparisons

Source-backed strengths

Evidence supports a direct mechanistic connection between the APB domain and interaction with light-activated phyB. In PIF4 and PIF5, APB-dependent degradation is preceded by phosphorylation and is sensitive to proteasome inhibitors, providing a defined route from light input to protein destabilization.

Ranked Citations

  1. 1.
    StructuralSource 1The Plant Journal2007Claim 1Claim 2Claim 3

    Extracted from this source document.