blue light signaling pathway

Definition

Target type: biologicalprocess

The series of molecular signals initiated upon sensing of blue light by photoreceptor molecule, at a wavelength between 400nm and 470nm. [GOC:lr, GOC:sm]

Blue light signaling is a crucial process in plants, enabling them to respond to changes in light conditions. It involves a complex network of photoreceptors, signaling molecules, and downstream targets that orchestrate diverse physiological responses.

The primary photoreceptors responsible for blue light perception are cryptochromes (CRYs) and phototropins (PHOTs).

* **Cryptochromes** are flavoproteins that absorb blue light and initiate a signaling cascade. Upon light absorption, CRY undergoes a conformational change, leading to the dissociation of its repressor domain. This allows the CRY to interact with and regulate transcription factors, altering gene expression.

* **Phototropins** are another family of blue light receptors that primarily mediate phototropism, the directional growth of plants towards light. They contain two light, oxygen, and voltage (LOV) domains, each containing a flavin mononucleotide (FMN) cofactor. Upon blue light absorption, the FMN undergoes a conformational change, leading to autophosphorylation of the phototropin molecule. This phosphorylation event initiates a signaling cascade that leads to the activation of downstream targets.

These signaling pathways converge on a variety of cellular processes, including:

1. **Phototropism**: Plants bend towards light sources to maximize light capture for photosynthesis. This response is mediated by phototropins, which control the asymmetric distribution of auxin, a plant hormone that regulates growth.

2. **Chloroplast movement**: Chloroplasts, the organelles responsible for photosynthesis, reposition themselves within the cell in response to blue light. This movement is driven by phototropins and ensures optimal light capture and avoids photodamage.

3. **Stomatal opening**: Blue light promotes stomatal opening, allowing for the uptake of carbon dioxide for photosynthesis.

4. **Gene regulation**: Cryptochromes and phototropins can directly regulate gene expression by interacting with transcription factors. These genes are involved in a wide range of processes, including photosynthesis, flowering, and development.

5. **Circadian rhythm**: Blue light plays a crucial role in synchronizing the plant's internal clock, influencing daily rhythms in gene expression, metabolism, and physiological processes.

The blue light signaling pathway is a sophisticated and dynamic system that allows plants to adapt and thrive in fluctuating light environments. This pathway underpins fundamental processes that are essential for plant growth, development, and survival.
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Proteins (2)

Compounds (1)