Synthesis and assembly of the PSII core subunits

Plants have many proteins found in the light-harvesting complex, whereas cyanobacteria have only the high-light-inducible proteins (Hlips).  One-helix proteins (OHPs) are the plant homologs of Hlips, but their precise functions have been unclear. Hey and Grimm used genetic and biochemical approaches to explore OHP function in Arabidopsis. The two Arabidopsis OHPs, OHP1 and OHP2, heterodimerize and also interact with the PSII assembly factor HIGH CHLOROPHYLL FLUORESCENCE 244 (HCF244). Interestingly, the stability of the three proteins is dependent on them accumulating concurrently. In VIGS-OHP2 plants (virally silenced OHP2), levels of core PSII subunits including D1 were also diminished, indicating that OHPs have similar functions to cyanobacterial Hlips. (Summary by Mary Williams) Plant Physiol. 10.1104/pp.18.00540