UniProt functional annotation for O22265



	UniProt functional annotation for O22265

UniProt code: O22265.

Organism: Arabidopsis thaliana (Mouse-ear cress).

Taxonomy: Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta; Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae; rosids; malvids; Brassicales; Brassicaceae; Camelineae; Arabidopsis.

Function: Component of the chloroplast signal recognition particle pathway. Required for post-translational targeting of proteins into the thylakoid membrane but seems to be dispensable for co-translational targeting with a translating ribosome present. May be able to function independently of cpFTSY and FFC/cpSRP54 in targeting LHCPs to the thylakoids. Acts as a highly specific chaperone for LHCPs, preventing aggregation and being able to dissolve aggregates. {ECO:0000269|PubMed:10480939, ECO:0000269|PubMed:15292240, ECO:0000269|PubMed:17513500, ECO:0000269|PubMed:20498370, ECO:0000269|PubMed:9878634}.

Subunit: Homodimer. Component of the cpSRP complex, composed of a FFC/cpSRP54 monomer and a CAO/cpSRP43 dimer. Interacts (via chromo domains 2 and 3) with ALB3 (via C-terminus), but not with ALB3L1/ALB4. Can interact simultaneously with ALB3 and FFC/cpSRP54. Interacts with LHCP and LTD. {ECO:0000269|PubMed:10480939, ECO:0000269|PubMed:11306572, ECO:0000269|PubMed:15292240, ECO:0000269|PubMed:16183644, ECO:0000269|PubMed:17513500, ECO:0000269|PubMed:18621669, ECO:0000269|PubMed:20018841, ECO:0000269|PubMed:20828566, ECO:0000269|PubMed:21505433}.

Subcellular location: Plastid, chloroplast stroma {ECO:0000269|PubMed:9878634}.

Tissue specificity: Expressed in leaves. Detected in roots. {ECO:0000269|PubMed:16813577, ECO:0000269|PubMed:9878634}.

Domain: The binding to LHCP occurs through the first ankyrin repeat and the L18 domain of LHCP.

Domain: Homodimerization occurs through both the third and the fourth ankyrin repeats.

Domain: Chromo domain 1 may act as a negative regulator of GTP hydrolysis by FFC/cpSRP54. It is unnecessary for targeting complex formation but is required for integration into the thylakoid membrane.

Domain: Chromo domain 2 is involved in binding to the M domain of FFC/cpSRP54.

Disruption phenotype: Plants show a reduced level of the major light- harvesting chlorophyll a/b-binding proteins (LHCPs). {ECO:0000269|PubMed:9878634}.

Miscellaneous: Unlike eukaryotic or prokaryotic signal recognition particle (SRP), the chloroplast SRP from higher plants lacks an SRP-RNA component. It targets both chloroplast-encoded and nucleus-encoded substrates to the thylakoid membrane, post-translationally for the nucleus-encoded proteins and co-translationally for the chloroplast- encoded proteins.

Annotations taken from UniProtKB at the EBI.


Organism:		Arabidopsis thaliana (Mouse-ear cress).
Taxonomy:		Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta; Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae; rosids; malvids; Brassicales; Brassicaceae; Camelineae; Arabidopsis.



Function:		Component of the chloroplast signal recognition particle pathway. Required for post-translational targeting of proteins into the thylakoid membrane but seems to be dispensable for co-translational targeting with a translating ribosome present. May be able to function independently of cpFTSY and FFC/cpSRP54 in targeting LHCPs to the thylakoids. Acts as a highly specific chaperone for LHCPs, preventing aggregation and being able to dissolve aggregates. {ECO:0000269\|PubMed:10480939, ECO:0000269\|PubMed:15292240, ECO:0000269\|PubMed:17513500, ECO:0000269\|PubMed:20498370, ECO:0000269\|PubMed:9878634}.


Subunit:		Homodimer. Component of the cpSRP complex, composed of a FFC/cpSRP54 monomer and a CAO/cpSRP43 dimer. Interacts (via chromo domains 2 and 3) with ALB3 (via C-terminus), but not with ALB3L1/ALB4. Can interact simultaneously with ALB3 and FFC/cpSRP54. Interacts with LHCP and LTD. {ECO:0000269\|PubMed:10480939, ECO:0000269\|PubMed:11306572, ECO:0000269\|PubMed:15292240, ECO:0000269\|PubMed:16183644, ECO:0000269\|PubMed:17513500, ECO:0000269\|PubMed:18621669, ECO:0000269\|PubMed:20018841, ECO:0000269\|PubMed:20828566, ECO:0000269\|PubMed:21505433}.
Subcellular location:		Plastid, chloroplast stroma {ECO:0000269\|PubMed:9878634}.
Tissue specificity:		Expressed in leaves. Detected in roots. {ECO:0000269\|PubMed:16813577, ECO:0000269\|PubMed:9878634}.
Domain:		The binding to LHCP occurs through the first ankyrin repeat and the L18 domain of LHCP.
Domain:		Homodimerization occurs through both the third and the fourth ankyrin repeats.
Domain:		Chromo domain 1 may act as a negative regulator of GTP hydrolysis by FFC/cpSRP54. It is unnecessary for targeting complex formation but is required for integration into the thylakoid membrane.
Domain:		Chromo domain 2 is involved in binding to the M domain of FFC/cpSRP54.
Disruption phenotype:		Plants show a reduced level of the major light- harvesting chlorophyll a/b-binding proteins (LHCPs). {ECO:0000269\|PubMed:9878634}.
Miscellaneous:		Unlike eukaryotic or prokaryotic signal recognition particle (SRP), the chloroplast SRP from higher plants lacks an SRP-RNA component. It targets both chloroplast-encoded and nucleus-encoded substrates to the thylakoid membrane, post-translationally for the nucleus-encoded proteins and co-translationally for the chloroplast- encoded proteins.