Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038379 (strabismus)
 9,317 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During its development, a plant shoot progresses from a juvenile to an adult phase of vegetative growth and from a reproductively incompetent to a reproductively competent state. In Arabidopsis, loss-of-function mutations in SQUINT (SQN) reduced the number of juvenile leaves and had subtle effects on inflorescence morphology but had no effect on flowering time or on reproductive competence. SQN encodes the Arabidopsis homolog of cyclophilin 40 (CyP40), a protein found in association with the Hsp90 chaperone complex in yeast, mammals, and plants. Thus, in Arabidopsis, CyP40 is specifically required for the vegetative but not the reproductive maturation of the shoot.
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PMID:Regulation of vegetative phase change in Arabidopsis thaliana by cyclophilin 40. 1126 35

Loss-of-function mutations of SQUINT (SQN)-which encodes the Arabidopsis orthologue of cyclophilin 40 (CyP40)-cause the precocious expression of adult vegetative traits, an increase in carpel number, and produce abnormal spacing of flowers in the inflorescence. Here we show that the vegetative phenotype of sqn is attributable to the elevated expression of miR156-regulated members of the SPL family of transcription factors and provide evidence that this defect is a consequence of a reduction in the activity of ARGONAUTE1 (AGO1). Support for this latter conclusion was provided by the phenotypic similarity between hypomorphic alleles of AGO1 and null alleles of SQN and by the genetic interaction between sqn and these alleles. Our results suggest that AGO1, or an AGO1-interacting protein, is a major client of CyP40 and that miR156 and its targets play a central role in the regulation of vegetative phase change in Arabidopsis.
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PMID:Cyclophilin 40 is required for microRNA activity in Arabidopsis. 1928 49

SQN (SQUINT) is the Arabidopsis ortholog of the immunophilin CyP40 (cyclophilin 40) and promotes microRNA activity by promoting the activity of AGO1. In animals and Saccharomyces cerevisiae, CyP40 promotes protein activity in association with the protein chaperone Hsp90. To determine whether CyP40 also acts in association with Hsp90 in plants, we examined the interaction between SQN and Hsp90 in vitro and tested the importance of this interaction for the function of SQN in planta. We found that SQN interacts with cytoplasmic Hsp90 proteins but not with Hsp90 proteins localized to chloroplasts, mitochondria, or the endoplasmic reticulum. The interaction between SQN and Hsp90 in vitro requires the MEEVD domain of Hsp90, as well as several conserved amino acids within the tetratricopeptide repeat domain of SQN. Amino acid substitutions that disrupt the interaction between SQN and Hsp90 in vitro also impair the activity of SQN in planta. Our results indicate that the interaction between CyP40 and Hsp90 is conserved in plants and that this interaction is essential for the function of CyP40.
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PMID:Binding of the cyclophilin 40 ortholog SQUINT to Hsp90 protein is required for SQUINT function in Arabidopsis. 2190 11