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Liu HW, Urzica EI, Gallaher SD, Schmollinger S, Blaby-Haas CE, Iwai M, Merchant SS. Chlamydomonas cells transition through distinct Fe nutrition stages within 48 h of transfer to Fe-free medium. PHOTOSYNTHESIS RESEARCH 2024:10.1007/s11120-024-01103-8. [PMID: 39017982 DOI: 10.1007/s11120-024-01103-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 05/15/2024] [Indexed: 07/18/2024]
Abstract
Low iron (Fe) bioavailability can limit the biosynthesis of Fe-containing proteins, which are especially abundant in photosynthetic organisms, thus negatively affecting global primary productivity. Understanding cellular coping mechanisms under Fe limitation is therefore of great interest. We surveyed the temporal responses of Chlamydomonas (Chlamydomonas reinhardtii) cells transitioning from an Fe-rich to an Fe-free medium to document their short and long-term adjustments. While slower growth, chlorosis and lower photosynthetic parameters are evident only after one or more days in Fe-free medium, the abundance of some transcripts, such as those for genes encoding transporters and enzymes involved in Fe assimilation, change within minutes, before changes in intracellular Fe content are noticeable, suggestive of a sensitive mechanism for sensing Fe. Promoter reporter constructs indicate a transcriptional component to this immediate primary response. With acetate provided as a source of reduced carbon, transcripts encoding respiratory components are maintained relative to transcripts encoding components of photosynthesis and tetrapyrrole biosynthesis, indicating metabolic prioritization of respiration over photosynthesis. In contrast to the loss of chlorophyll, carotenoid content is maintained under Fe limitation despite a decrease in the transcripts for carotenoid biosynthesis genes, indicating carotenoid stability. These changes occur more slowly, only after the intracellular Fe quota responds, indicating a phased response in Chlamydomonas, involving both primary and secondary responses during acclimation to poor Fe nutrition.
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Affiliation(s)
- Helen W Liu
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 99354, USA
| | - Eugen I Urzica
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
- Competence Network IBD, Hopfenstrasse 60, 24103, Kiel, Germany
| | - Sean D Gallaher
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, 94720, USA
| | - Stefan Schmollinger
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, 94720, USA
- Plant Research Laboratory, Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Crysten E Blaby-Haas
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Masakazu Iwai
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Sabeeha S Merchant
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 99354, USA.
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA.
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, 94720, USA.
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA.
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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Wolfram M, Greif A, Baidukova O, Voll H, Tauber S, Lindacher J, Hegemann P, Kreimer G. Insights into degradation and targeting of the photoreceptor channelrhodopsin-1. PLANT, CELL & ENVIRONMENT 2024. [PMID: 38935876 DOI: 10.1111/pce.15017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 06/05/2024] [Accepted: 06/11/2024] [Indexed: 06/29/2024]
Abstract
In Chlamydomonas, the directly light-gated, plasma membrane-localized cation channels channelrhodopsins ChR1 and ChR2 are the primary photoreceptors for phototaxis. Their targeting and abundance is essential for optimal movement responses. However, our knowledge how Chlamydomonas achieves this is still at its infancy. Here we show that ChR1 internalization occurs via light-stimulated endocytosis. Prior or during endocytosis ChR1 is modified and forms high molecular mass complexes. These are the solely detectable ChR1 forms in extracellular vesicles and their abundance therein dynamically changes upon illumination. The ChR1-containing extracellular vesicles are secreted via the plasma membrane and/or the ciliary base. In line with this, ciliogenesis mutants exhibit increased ChR1 degradation rates. Further, we establish involvement of the cysteine protease CEP1, a member of the papain-type C1A subfamily. ΔCEP1-knockout strains lack light-induced ChR1 degradation, whereas ChR2 degradation was unaffected. Low light stimulates CEP1 expression, which is regulated via phototropin, a SPA1 E3 ubiquitin ligase and cyclic AMP. Further, mutant and inhibitor analyses revealed involvement of the small GTPase ARL11 and SUMOylation in ChR1 targeting to the eyespot and cilia. Our study thus defines the degradation pathway of this central photoreceptor of Chlamydomonas and identifies novel elements involved in its homoeostasis and targeting.
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Affiliation(s)
- Michaela Wolfram
- Department of Biology, Cell Biology, Friedrich-Alexander Universität, Erlangen-Nürnberg, Germany
| | - Arne Greif
- Department of Biology, Cell Biology, Friedrich-Alexander Universität, Erlangen-Nürnberg, Germany
| | - Olga Baidukova
- Institute of Biology, Experimental Biophysics, Humboldt Universität, Berlin, Germany
| | - Hildegard Voll
- Department of Biology, Cell Biology, Friedrich-Alexander Universität, Erlangen-Nürnberg, Germany
| | - Sandra Tauber
- Department of Biology, Cell Biology, Friedrich-Alexander Universität, Erlangen-Nürnberg, Germany
| | - Jana Lindacher
- Department of Biology, Cell Biology, Friedrich-Alexander Universität, Erlangen-Nürnberg, Germany
| | - Peter Hegemann
- Institute of Biology, Experimental Biophysics, Humboldt Universität, Berlin, Germany
| | - Georg Kreimer
- Department of Biology, Cell Biology, Friedrich-Alexander Universität, Erlangen-Nürnberg, Germany
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Docampo R. Advances in the cellular biology, biochemistry, and molecular biology of acidocalcisomes. Microbiol Mol Biol Rev 2024; 88:e0004223. [PMID: 38099688 PMCID: PMC10966946 DOI: 10.1128/mmbr.00042-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2024] Open
Abstract
SUMMARYAcidocalcisomes are organelles conserved during evolution and closely related to the so-called volutin granules of bacteria and archaea, to the acidocalcisome-like vacuoles of yeasts, and to the lysosome-related organelles of animal species. All these organelles have in common their acidity and high content of polyphosphate and calcium. They are characterized by a variety of functions from storage of phosphorus and calcium to roles in Ca2+ signaling, osmoregulation, blood coagulation, and inflammation. They interact with other organelles through membrane contact sites or by fusion, and have several enzymes, pumps, transporters, and channels.
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Affiliation(s)
- Roberto Docampo
- Department of Cellular Biology, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
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Strenkert D, Schmollinger S, Paruthiyil S, Brown BC, Green S, Shafer CM, Salomé P, Nelson H, Blaby-Haas CE, Moseley JL, Merchant SS. Distinct function of Chlamydomonas CTRA-CTR transporters in Cu assimilation and intracellular mobilization. Metallomics 2024; 16:mfae013. [PMID: 38439674 PMCID: PMC10959442 DOI: 10.1093/mtomcs/mfae013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 03/02/2024] [Indexed: 03/06/2024]
Abstract
Successful acclimation to copper (Cu) deficiency involves a fine balance between Cu import and export. In the green alga Chlamydomonas reinhardtii, Cu import is dependent on a transcription factor, Copper Response Regulator 1 (CRR1), responsible for activating genes in Cu-deficient cells. Among CRR1 target genes are two Cu transporters belonging to the CTR/COPT gene family (CTR1 and CTR2) and a related soluble protein (CTR3). The ancestor of these green algal proteins was likely acquired from an ancient chytrid and contained conserved cysteine-rich domains (named the CTR-associated domains, CTRA) that are predicted to be involved in Cu acquisition. We show by reverse genetics that Chlamydomonas CTR1 and CTR2 are canonical Cu importers albeit with distinct affinities, while loss of CTR3 did not result in an observable phenotype under the conditions tested. Mutation of CTR1, but not CTR2, recapitulates the poor growth of crr1 in Cu-deficient medium, consistent with a dominant role for CTR1 in high-affinity Cu(I) uptake. On the other hand, the overaccumulation of Cu(I) (20 times the quota) in zinc (Zn) deficiency depends on CRR1 and both CTR1 and CTR2. CRR1-dependent activation of CTR gene expression needed for Cu over-accumulation can be bypassed by the provision of excess Cu in the growth medium. Over-accumulated Cu is sequestered into the acidocalcisome but can become remobilized by restoring Zn nutrition. This mobilization is also CRR1-dependent, and requires activation of CTR2 expression, again distinguishing CTR2 from CTR1 and consistent with the lower substrate affinity of CTR2. ONE SENTENCE SUMMARY Regulation of Cu uptake and sequestration by members of the CTR family of proteins in Chlamydomonas.
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Affiliation(s)
- Daniela Strenkert
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | - Stefan Schmollinger
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | - Srinand Paruthiyil
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | - Bonnie C Brown
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Sydnee Green
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Catherine M Shafer
- Molecular Toxicology Inter-departmental Ph.D. program, University of California, Los Angeles, CA 90095, USA
| | - Patrice Salomé
- Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095, USA
| | - Hosea Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Crysten E Blaby-Haas
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jeffrey L Moseley
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | - Sabeeha S Merchant
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
- Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095, USA
- Department of Molecular and Cell Biology and Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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