TY - JOUR

T1 - Stop CRYing! Inhibition of cryptochrome function by small proteins

AU - Kruusvee, Valdeko

AU - Toft, Arendse Maria

AU - Aguida, Blanche

AU - Ahmad, Margaret

AU - Wenkel, Stephan

PY - 2022

Y1 - 2022

N2 - Plants can detect the presence of light using specialised photoreceptor proteins. These photoreceptors measure the intensity of light, but they can also respond to different spectra of light and thus 'see' different colours. Cryptochromes, which are also present in animals, are flavin-based photoreceptors that enable plants to detect blue and ultravio-let-A (UV-A) light. In Arabidopsis, there are two cryptochromes, CRYPTOCHROME 1 (CRY1) and CRYPTOCHROME 2 (CRY2) with known sensory roles. They function in various processes such as blue-light mediated inhibition of hypocotyl elongation, photo-periodic promotion of floral initiation, cotyledon expansion, anthocyanin production, and magnetoreception, to name a few. In the dark, the cryptochromes are in an inactive monomeric state and undergo photochemical and conformational change in response to illumination. This results in flavin reduction, oligomerisation, and the formation of the 'cryptochrome complexome'. Mechanisms of cryptochrome activation and signalling have been extensively studied and found to be conserved across phylogenetic lines. In this review, we will therefore focus on a far lesser-known mechanism of regulation that is unique to plant cryptochromes. This involves inhibition of cryptochrome activity by small proteins that prevent its dimerisation in response to light. The resulting inhibition of func-tion cause profound alterations in economically important traits such as plant growth, flowering, and fruit production. This review will describe the known mechanisms of cryp-tochrome activation and signalling in the context of their modulation by these endogen-ous and artificial small inhibitor proteins. Promising new applications for biotechnological and agricultural applications will be discussed.

AB - Plants can detect the presence of light using specialised photoreceptor proteins. These photoreceptors measure the intensity of light, but they can also respond to different spectra of light and thus 'see' different colours. Cryptochromes, which are also present in animals, are flavin-based photoreceptors that enable plants to detect blue and ultravio-let-A (UV-A) light. In Arabidopsis, there are two cryptochromes, CRYPTOCHROME 1 (CRY1) and CRYPTOCHROME 2 (CRY2) with known sensory roles. They function in various processes such as blue-light mediated inhibition of hypocotyl elongation, photo-periodic promotion of floral initiation, cotyledon expansion, anthocyanin production, and magnetoreception, to name a few. In the dark, the cryptochromes are in an inactive monomeric state and undergo photochemical and conformational change in response to illumination. This results in flavin reduction, oligomerisation, and the formation of the 'cryptochrome complexome'. Mechanisms of cryptochrome activation and signalling have been extensively studied and found to be conserved across phylogenetic lines. In this review, we will therefore focus on a far lesser-known mechanism of regulation that is unique to plant cryptochromes. This involves inhibition of cryptochrome activity by small proteins that prevent its dimerisation in response to light. The resulting inhibition of func-tion cause profound alterations in economically important traits such as plant growth, flowering, and fruit production. This review will describe the known mechanisms of cryp-tochrome activation and signalling in the context of their modulation by these endogen-ous and artificial small inhibitor proteins. Promising new applications for biotechnological and agricultural applications will be discussed.

KW - BLUE-LIGHT SENSITIVITY

KW - GENOME

KW - MEDIATE

KW - DNA

KW - TRANSCRIPTION

KW - INACTIVATION

KW - EVOLUTION

KW - DOMAIN

KW - CRY1

U2 - 10.1042/BST20190062

DO - 10.1042/BST20190062

M3 - Review

C2 - 35311888

VL - 50

SP - 773

EP - 782

JO - Biochemical Society Transactions

JF - Biochemical Society Transactions

SN - 0300-5127

IS - 2

ER -