Structural and functional analysis of tomato sterol C22 desaturase
Gutiérrez-García, Laura (Centre de Recerca en Agrigenòmica)
Arró i Plans, Montserrat (Centre de Recerca en Agrigenòmica)
Altabella Artigas, Teresa (Centre de Recerca en Agrigenòmica)
Ferrer, Albert (Centre de Recerca en Agrigenòmica)
Boronat i Margosa, Albert (Centre de Recerca en Agrigenòmica)

Data:	2021
Resum:	Background: Sterols are structural and functional components of eukaryotic cell membranes. Plants produce a complex mixture of sterols, among which β-sitosterol, stigmasterol, campesterol, and cholesterol in some Solanaceae, are the most abundant species. Many reports have shown that the stigmasterol to β-sitosterol ratio changes during plant development and in response to stresses, suggesting that it may play a role in the regulation of these processes. In tomato (Solanum lycopersicum), changes in the stigmasterol to β-sitosterol ratio correlate with the induction of the only gene encoding sterol C22-desaturase (C22DES), the enzyme specifically involved in the conversion of β-sitosterol to stigmasterol. However, despite the biological interest of this enzyme, there is still a lack of knowledge about several relevant aspects related to its structure and function. Results: In this study we report the subcellular localization of tomato C22DES in the endoplasmic reticulum (ER) based on confocal fluorescence microscopy and cell fractionation analyses. Modeling studies have also revealed that C22DES consists of two well-differentiated domains: a single N-terminal transmembrane-helix domain (TMH) anchored in the ER-membrane and a globular (or catalytic) domain that is oriented towards the cytosol. Although TMH is sufficient for the targeting and retention of the enzyme in the ER, the globular domain may also interact and be retained in the ER in the absence of the N-terminal transmembrane domain. The observation that a truncated version of C22DES lacking the TMH is enzymatically inactive revealed that the N-terminal membrane domain is essential for enzyme activity. The in silico analysis of the TMH region of plant C22DES revealed several structural features that could be involved in substrate recognition and binding. Conclusions: Overall, this study contributes to expand the current knowledge on the structure and function of plant C22DES and to unveil novel aspects related to plant sterol metabolism.
Ajuts:	Ministerio de Economía y Competitividad BES-2014-070425 Ministerio de Ciencia e Innovación AGL2017-88842-R Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-710 Ministerio de Economía y Competitividad SEV-2015-0533
Nota:	Altres ajuts: CERCA Programme/Generalitat de Catalunya
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Tomato ; Sterol metabolism, Stigmasterol ; β-Sitosterol ; Cytochrome P450 ; Sterol C22-desaturase, endoplasmic reticulum
Publicat a:	BMC plant biology, Vol. 21 (March 2021) , art. 141, ISSN 1471-2229

DOI: 10.1186/s12870-021-02898-7
PMID: 33731007

14 p, 6.0 MB

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