Regulation of chloroplast protein import by the ubiquitin E3 ligase SP1 is important for stress tolerance in plants

Ling, Q; Jarvis, P

Journal article

Regulation of chloroplast protein import by the ubiquitin E3 ligase SP1 is important for stress tolerance in plants

Abstract:: Chloroplasts are the organelles responsible for photosynthesis in plants. The chloroplast proteome comprises ∼3,000 different proteins, including components of the photosynthetic apparatus, which are highly abundant. Most chloroplast proteins are nucleus-encoded and imported following synthesis in the cytosol. Such import is mediated by multiprotein complexes in the envelope membranes that surround each organelle. The translocon at the outer envelope membrane of chloroplasts (TOC) mediates client protein recognition and early stages of import. The TOC apparatus is regulated by the ubiquitin-proteasome system (UPS) in a process controlled by the envelope-localized ubiquitin E3 ligase SUPPRESSOR OF PPI1 LOCUS1 (SP1). Previous work showed that SP1-mediated regulation of chloroplast protein import contributes to the organellar proteome changes that occur during plant development (e.g., during de-etiolation). Here, we reveal a critical role for SP1 in plant responses to abiotic stress, which is a major and increasing cause of agricultural yield losses globally. Arabidopsis plants lacking SP1 are hypersensitive to salt, osmotic, and oxidative stresses, whereas plants overexpressing SP1 are considerably more stress tolerant than wild-type. We present evidence that SP1 acts to deplete the TOC apparatus under stress conditions to limit the import of photosynthetic apparatus components, which may attenuate photosynthetic activity and reduce the potential for reactive oxygen species production and photo-oxidative damage. Our results indicate that chloroplast protein import is responsive to environmental cues, enabling dynamic regulation of the organellar proteome, and suggest new approaches for improving stress tolerance in crops.

Publication status:: Published

Peer review status:: Peer reviewed

Actions

Email

Email this record

Send the bibliographic details of this record to your email address.

Your Email
Please enter the email address that the record information will be sent to.

-
Your message (optional)
Please add any additional information to be included within the email.
Share
Cite

Cite this record

APA Style

Ling, Q., & Jarvis, P. (2015). Regulation of chloroplast protein import by the ubiquitin E3 ligase SP1 is important for stress tolerance in plants. Current Biology, 25(19), 2527–2534.

MLA Style

Ling, Q, and P Jarvis. “Regulation of Chloroplast Protein Import by the Ubiquitin E3 Ligase SP1 Is Important for Stress Tolerance in Plants.” Current Biology, vol. 25, no. 19, 2015, pp. 2527–34.

Chicago Style

Ling, Q, and P Jarvis. 2015. “Regulation of Chloroplast Protein Import by the Ubiquitin E3 Ligase SP1 Is Important for Stress Tolerance in Plants.” Current Biology 25 (19): 2527–34.
Print