ARL15 modulates magnesium homeostasis through N-glycosylation of CNNMs

Cyclin M (CNNM1-4) proteins maintain cellular and body magnesium (Mg2+) homeostasis. Using various biochemical approaches, we have identified members of the CNNM family as direct interacting partners of ADP-ribosylation factor-like GTPase 15 (ARL15), a small GTP-binding protein. ARL15 interacts with CNNMs at their carboxyl-terminal conserved cystathionine-β-synthase (CBS) domains. In silico modeling of the interaction between CNNM2 and ARL15 supports that the small GTPase specifically binds the CBS1 and CNBH domains. Immunocytochemical experiments demonstrate that CNNM2 and ARL15 co-localize in the kidney, with both proteins showing subcellular localization in the endoplasmic reticulum, Golgi apparatus and the plasma membrane. Most importantly, we found that ARL15 is required for forming complex N-glycosylation of CNNMs. Overexpression of ARL15 promotes complex N-glycosylation of CNNM3. Mg2+ uptake experiments with a stable isotope demonstrate that there is a significant increase of 25Mg2+ uptake upon knockdown of ARL15 in multiple kidney cancer cell lines. Altogether, our results establish ARL15 as a novel negative regulator of Mg2+ transport by promoting the complex N-glycosylation of CNNMs.European Joint Program for Rare Diseases (EJPRD2019-40)Spanish Ministry of Science and Innovation and Universities (PGC2018-096049-B-I00)Junta de Andalucía (BIO-198, US-1254317 and US-1257019

Analysis of plant dehydrin promoters

Transcriptional regulation is an important mechanism of gene expression modulation. The two studies presented here looked at transcriptional control of dehydrin genes. In the first study, promoters of KS dehydrin orthologues from an arctic and temperate Oxytropis species were compared. A region in the promoter from the temperate species was identified to be responsible for the repression of expression of a reporter gene under the promoter’s control. In the second study, using de novo motif discovery, promoters of five subclasses of dehydrins were analyzed. It was shown that each subclass contains overrepresented motifs in their promoters, which could help explain dehydrins’ expression patterns in response to various environmental stresses.La régulation transcriptionnelle est un mécanisme important de la modulation de l'expression génique. Les deux études présentées ici ont examiné le contrôle transcriptionnel de gènes de type déhydrine. Dans la première étude, les promoteurs de deux orthologues de déhydrine KS des espèces arctique et tempérée du genre Oxytropis ont été comparés. Une région dans le promoteur de l'espèce tempérée a été identifiée comme étant responsable de la répression d'expression d'un gène rapporteur sous le contrôle du promoteur. Dans la deuxième étude, à l'aide de la découverte de motifs de novo, les promoteurs des cinq sous-classes de déhydrines ont été analysés. Il a été démontré que chaque sous-classe contient des motifs surreprésentés dans leurs promoteurs, ce qui pourrait aider à expliquer les profils d'expression de déhydrines en réponse aux divers stress environnementaux

Selected <i>de novo</i> motifs found in Y_nSK_n dehydrin promoters and their putative function identified through PLACE database.

<p>¹Number of the motif and the <i>de novo</i> discovery software that was used to locate that motif.</p><p>²Motif consensus sequence in IUPAC nucleotide code.</p><p>³Occurrence is the number of promoters containing a <i>de novo</i> motif out of the total number of promoters analyzed for a specific dehydrin class, presented in the parentheses.</p><p>⁴Siginificance of the motif, E-value calculated by MEME, Q-value calculated by Seeder, presented in the parentheses.</p><p>⁵PLACE matches were identified using STAMP, only significant matches with E-value < 0.05 are presented.</p><p>⁶E-value of the match with PLACE motif.</p><p>Selected <i>de novo</i> motifs found in Y_nSK_n dehydrin promoters and their putative function identified through PLACE database.</p

Selected <i>de novo</i> motifs found in K_n dehydrin promoters and their putative function identified through PLACE database.

<p>¹Number of the motif and the <i>de novo</i> discovery software that was used to locate that motif.</p><p>²Motif consensus sequence in IUPAC nucleotide code.</p><p>³Occurrence is the number of promoters containing a <i>de novo</i> motif out of the total number of promoters analyzed for a specific dehydrin class, presented in the parentheses.</p><p>⁴Siginificance of the motif, E-value calculated by MEME, Q-value calculated by Seeder, presented in the parentheses.</p><p>⁵PLACE matches were identified using STAMP, only significant matches with E-value < 0.05 are presented.</p><p>⁶E-value of the match with PLACE motif.</p><p>Selected <i>de novo</i> motifs found in K_n dehydrin promoters and their putative function identified through PLACE database.</p

Selected <i>de novo</i> motifs found in KS dehydrin promoters and their putative function identified through PLACE database.

<p>¹Number of the motif and the <i>de novo</i> discovery software that was used to locate that motif.</p><p>²Motif consensus sequence in IUPAC nucleotide code.</p><p>³Occurrence is the number of promoters containing a <i>de novo</i> motif out of the total number of promoters analyzed for a specific dehydrin class, presented in the parentheses.</p><p>⁴Siginificance of the motif, E-value calculated by MEME, Q-value calculated by Seeder, presented in the parentheses.</p><p>⁵PLACE matches were identified using STAMP, only significant matches with E-value < 0.05 are presented.</p><p>⁶E-value of the match with PLACE motif.</p><p>Selected <i>de novo</i> motifs found in KS dehydrin promoters and their putative function identified through PLACE database.</p