High impact information on HCF136

• Immunoblot analysis of fractionated chloroplasts showed that the HCF136 protein is a lumenal protein, found only in stromal thylakoid lamellae [1].
• We conclude that HCF136 encodes a stability and/or assembly factor of PSII which dates back to the cyanobacterial-like endosymbiont that led to the plastids of the present photosynthetic eukaryotes [1].
• We demonstrate by in vivo radiolabeling of hcf136 that biogenesis of the reaction center (RC) of PSII is blocked [2].
• However, twin-arginine motifs are absent from the presequences of Hcf136 proteins encoded by plastid or cyanobacterial genomes, strongly implying translocation by another pathway (presumably Sec) [3].

Biological context of HCF136

• We suggest that the Hcf136 protein was transferred to the Tat pathway when the gene became incorporated into the nuclear genome, possibly due to the tighter folding associated with the more involved, post-translational targeting pathway [3].

Analytical, diagnostic and therapeutic context of HCF136

• Gel blot analysis and affinity chromatography of solubilized thylakoid membranes suggest that HCF136p associates with a PSII precomplex containing at least D2 and cytochrome b(559) [2].

References