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Phosphoproteomic analysis of Chlamydomonas PetD mutants

ABSTRACT: The cytochrome b6f complex (b6f) links photosystem II and photosystem I in photosynthetic electron transfer and is distributed between appressed and non-appressed thylakoid membranes. It also activates the state-transition 7 kinase (STT7), which phosphorylates light-harvesting complex proteins, facilitating energy redistribution between photosystems to optimize their efficiency. To investigate the role of STT7-dependent phosphorylation at T4 in the N-terminal domain of the b6f subunit-IV (PetD), we generated several chloroplast mutants. The phosphomimic mutation PetD T4E blocks STT7 kinase activity since proteomics show the absence of STT7-dependent phosphorylation and the strain being locked in State 1, revealing a novel feedback regulation mechanism. The deletion of five N-terminal amino acids resulted in a comparable inhibition of STT7 activity; furthermore, the additional disruption of electron transfer underscores an additional crucial role of the PetD N-terminus in b6f function.

INSTRUMENT(S):

ORGANISM(S): Chlamydomonas Reinhardtii

TISSUE(S): Photosynthetic Cell

SUBMITTER: Martin Scholz

LAB HEAD: Michael Hippler

PROVIDER: PXD060640 | Pride | 2026-04-04

REPOSITORIES: Pride

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			Action	DRS
	AZ_20240817_anox_H6F5cas20_1.raw	Raw
	AZ_20240817_anox_H6F5cas20_1_P1.raw	Raw
	AZ_20240817_anox_H6F5cas20_1_P2.raw	Raw
	AZ_20240817_anox_H6F5cas20_1_P3.raw	Raw
	AZ_20240817_anox_H6F5cas20_2.raw	Raw

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Phosphoproteomic analysis of Chlamydomonas PetD mutants

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