Source 1primary paper2004Biochemistry
Toolkit/Jalpha helix
Jalpha helix
Also known as: Jalpha, Jα helix
Taxonomy: Mechanism Branch / Component. Workflows sit above the mechanism and technique branches rather than replacing them.
Summary
The Jalpha helix is a helical element external to a LOV domain in phototropin proteins that regulates light-dependent kinase signaling. Source literature indicates that unfolding or displacement of the Jalpha helix from the LOV domain activates signaling, and point mutations can induce this displaced state independently of illumination.
Usefulness & Problems
Why this is useful
This domain is useful as a regulatory element for coupling LOV-domain photoreception to downstream signaling output. The cited evidence supports its use for probing or engineering light-regulated conformational control of kinase activity.
Problem solved
The Jalpha helix helps solve the problem of how light input is converted into activation of phototropin kinase signaling. The supplied evidence specifically identifies Jalpha unfolding or LOV-Jalpha interaction disruption as the critical regulatory event.
Taxonomy & Function
Primary hierarchy
Mechanism Branch
Component: A low-level protein part used inside a larger architecture that realizes a mechanism.
Mechanisms
Degradationhelix unfoldinglight-regulated conformational switchinglov-jalpha interaction disruptionTechniques
No technique tags yet.
Target processes
degradationsignalingInput: Light
Implementation Constraints
The evidence supports implementation through point mutagenesis of the Jalpha helix to disrupt its interaction with the LOV domain and promote a constitutively displaced state. No additional practical details on cofactors, host systems, construct architecture, or delivery are provided in the supplied material.
The supplied evidence is limited to mechanistic conclusions about phototropin kinase regulation and does not provide quantitative performance data, wavelength dependence, reversibility, or cross-system validation. Although degradation appears in the metadata, no direct supporting evidence for a degradation-related function is provided here.
Validation
Cell-freeBacteriaMammalianMouseHumanTherapeuticIndep. Replication
Supporting Sources
Ranked Claims
Unfolding of the Jalpha helix is the critical event regulating kinase signaling in phototropin proteins.
These results indicate that unfolding of the Jalpha helix is the critical event in regulation of kinase signaling for the phototropin proteins.
Several Jalpha helix point mutations displace the Jalpha helix from the LOV domain independently of illumination.
Using NMR spectroscopy and limited proteolysis, we demonstrate that several of these mutations displace the Jalpha helix from the LOV domain independently of illumination.
Approval Evidence
1 source2 linked approval claimsfirst-pass slug jalpha-helix
a helix external to this domain called Jalpha
Source:
mechanistic conclusionsupports
Unfolding of the Jalpha helix is the critical event regulating kinase signaling in phototropin proteins.
These results indicate that unfolding of the Jalpha helix is the critical event in regulation of kinase signaling for the phototropin proteins.
Source:
mechanistic effectsupports
Several Jalpha helix point mutations displace the Jalpha helix from the LOV domain independently of illumination.
Using NMR spectroscopy and limited proteolysis, we demonstrate that several of these mutations displace the Jalpha helix from the LOV domain independently of illumination.
Source:
Comparisons
Source-backed strengths
The available evidence assigns a specific mechanistic role to the Jalpha helix in phototropin signaling rather than a merely correlative association. It is also supported that several point mutations can displace the helix from the LOV domain without illumination, indicating a genetically tunable regulatory switch.
Ranked Citations
- 1.