Disease relevance of SOS4

• The expression of SOS4 cDNAs complements an Escherichia coli mutant defective in pyridoxal kinase [1].

High impact information on SOS4

• As a result of alternative splicing, two transcripts are derived from the SOS4 gene, the relative abundance of which is modulated by development and environmental stresses [1].
• The Arabidopsis salt overly sensitive 4 mutants uncover a critical role for vitamin B6 in plant salt tolerance [1].
• Supplementation of pyridoxine but not pyridoxal in the growth medium can partially rescue the sos4 defect in salt tolerance [1].
• SOS4 encodes a pyridoxal kinase that is involved in the biosynthesis of pyridoxal-5-phosphate, an active form of vitamin B6 [1].
• Our results demonstrate that pyridoxal kinase is a novel salt tolerance determinant important for the regulation of Na(+) and K(+) homeostasis in plants [1].

Biological context of SOS4

• The root hairless phenotype of sos4 mutants was complemented by the wild-type SOS4 gene [2].
• The amino acid sequence of the A. thaliana PK was found to be similar to the mammalian enzyme, with a homology of more than 40% [3].

Associations of SOS4 with chemical compounds

• The possible role of SOS4 in ethylene and auxin biosynthesis is discussed [2].
• The SOS4 (Salt Overly Sensitive 4) gene was recently isolated by map-based cloning and shown to encode a pyridoxal (PL) kinase involved in the production of PL-5-phosphate, which is an important cofactor for various enzymes and a ligand for certain ion transporters [2].
• Consistent with SOS4 function as a PL kinase, in vitro application of pyridoxine and pyridoxamine, but not PL, partially rescued the root hair defect in sos4 mutants [2].

References