Full text data of LSM4
LSM4
[Confidence: low (only semi-automatic identification from reviews)]
U6 snRNA-associated Sm-like protein LSm4 (Glycine-rich protein; GRP)
Note: presumably soluble (membrane word is not in UniProt keywords or features)
U6 snRNA-associated Sm-like protein LSm4 (Glycine-rich protein; GRP)
Note: presumably soluble (membrane word is not in UniProt keywords or features)
UniProt
Q9Y4Z0
ID LSM4_HUMAN Reviewed; 139 AA.
AC Q9Y4Z0;
DT 01-DEC-2000, integrated into UniProtKB/Swiss-Prot.
read moreDT 01-NOV-1999, sequence version 1.
DT 22-JAN-2014, entry version 120.
DE RecName: Full=U6 snRNA-associated Sm-like protein LSm4;
DE AltName: Full=Glycine-rich protein;
DE Short=GRP;
GN Name=LSM4;
OS Homo sapiens (Human).
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini;
OC Catarrhini; Hominidae; Homo.
OX NCBI_TaxID=9606;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA].
RC TISSUE=Liver;
RX PubMed=10369684; DOI=10.1093/emboj/18.12.3451;
RA Salgado-Garrido J., Bragado-Nilsson E., Kandels-Lewis S., Seraphin B.;
RT "Sm and Sm-like proteins assemble in two related complexes of deep
RT evolutionary origin.";
RL EMBO J. 18:3451-3462(1999).
RN [2]
RP NUCLEOTIDE SEQUENCE [MRNA], AND PARTIAL PROTEIN SEQUENCE.
RX PubMed=10523320; DOI=10.1093/emboj/18.20.5789;
RA Achsel T., Brahms H., Kastner B., Bachi A., Wilm M., Luehrmann R.;
RT "A doughnut-shaped heteromer of human Sm-like proteins binds to the
RT 3'-end of U6 snRNA, thereby facilitating U4/U6 duplex formation in
RT vitro.";
RL EMBO J. 18:5789-5802(1999).
RN [3]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RC TISSUE=Hypothalamus;
RX PubMed=10931946; DOI=10.1073/pnas.160270997;
RA Hu R.-M., Han Z.-G., Song H.-D., Peng Y.-D., Huang Q.-H., Ren S.-X.,
RA Gu Y.-J., Huang C.-H., Li Y.-B., Jiang C.-L., Fu G., Zhang Q.-H.,
RA Gu B.-W., Dai M., Mao Y.-F., Gao G.-F., Rong R., Ye M., Zhou J.,
RA Xu S.-H., Gu J., Shi J.-X., Jin W.-R., Zhang C.-K., Wu T.-M.,
RA Huang G.-Y., Chen Z., Chen M.-D., Chen J.-L.;
RT "Gene expression profiling in the human hypothalamus-pituitary-adrenal
RT axis and full-length cDNA cloning.";
RL Proc. Natl. Acad. Sci. U.S.A. 97:9543-9548(2000).
RN [4]
RP NUCLEOTIDE SEQUENCE [MRNA].
RA Chan E.K.L.;
RL Submitted (APR-2000) to the EMBL/GenBank/DDBJ databases.
RN [5]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RC TISSUE=Lung;
RX PubMed=15489334; DOI=10.1101/gr.2596504;
RG The MGC Project Team;
RT "The status, quality, and expansion of the NIH full-length cDNA
RT project: the Mammalian Gene Collection (MGC).";
RL Genome Res. 14:2121-2127(2004).
RN [6]
RP PROTEIN SEQUENCE OF 1-20, ACETYLATION AT MET-1, AND MASS SPECTROMETRY.
RC TISSUE=Mammary carcinoma;
RA Bienvenut W.V., Matallanas D., Cooper W.N., Kolch W.;
RL Submitted (JUL-2007) to UniProtKB.
RN [7]
RP IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
RX PubMed=21269460; DOI=10.1186/1752-0509-5-17;
RA Burkard T.R., Planyavsky M., Kaupe I., Breitwieser F.P.,
RA Buerckstuemmer T., Bennett K.L., Superti-Furga G., Colinge J.;
RT "Initial characterization of the human central proteome.";
RL BMC Syst. Biol. 5:17-17(2011).
CC -!- FUNCTION: Binds specifically to the 3'-terminal U-tract of U6
CC snRNA.
CC -!- SUBUNIT: LSm subunits form a heteromer with a doughnut shape.
CC -!- INTERACTION:
CC Q9UK45:LSM7; NbExp=6; IntAct=EBI-372521, EBI-348372;
CC O95777:NAA38; NbExp=4; IntAct=EBI-372521, EBI-347779;
CC -!- SUBCELLULAR LOCATION: Nucleus (Potential).
CC -!- SIMILARITY: Belongs to the snRNP Sm proteins family.
CC -----------------------------------------------------------------------
CC Copyrighted by the UniProt Consortium, see http://www.uniprot.org/terms
CC Distributed under the Creative Commons Attribution-NoDerivs License
CC -----------------------------------------------------------------------
DR EMBL; AJ238096; CAB45867.1; -; mRNA.
DR EMBL; AF182290; AAD56228.1; -; mRNA.
DR EMBL; AF117235; AAF17216.1; -; mRNA.
DR EMBL; AF251218; AAF90055.1; -; mRNA.
DR EMBL; BC000387; AAH00387.1; -; mRNA.
DR EMBL; BC003652; AAH03652.1; -; mRNA.
DR EMBL; BC022198; AAH22198.1; -; mRNA.
DR EMBL; BC023665; AAH23665.1; -; mRNA.
DR RefSeq; NP_036453.1; NM_012321.4.
DR UniGene; Hs.515255; -.
DR ProteinModelPortal; Q9Y4Z0; -.
DR SMR; Q9Y4Z0; 14-71.
DR DIP; DIP-31209N; -.
DR IntAct; Q9Y4Z0; 16.
DR MINT; MINT-1469332; -.
DR STRING; 9606.ENSP00000252816; -.
DR PhosphoSite; Q9Y4Z0; -.
DR DMDM; 10720082; -.
DR PaxDb; Q9Y4Z0; -.
DR PeptideAtlas; Q9Y4Z0; -.
DR PRIDE; Q9Y4Z0; -.
DR DNASU; 25804; -.
DR Ensembl; ENST00000593829; ENSP00000469468; ENSG00000130520.
DR GeneID; 25804; -.
DR KEGG; hsa:25804; -.
DR UCSC; uc002niq.3; human.
DR CTD; 25804; -.
DR GeneCards; GC19M018417; -.
DR HGNC; HGNC:17259; LSM4.
DR HPA; HPA040932; -.
DR MIM; 607284; gene.
DR neXtProt; NX_Q9Y4Z0; -.
DR PharmGKB; PA134906569; -.
DR eggNOG; COG1958; -.
DR HOGENOM; HOG000182713; -.
DR HOVERGEN; HBG000486; -.
DR InParanoid; Q9Y4Z0; -.
DR KO; K12623; -.
DR OMA; GMQQQKQ; -.
DR OrthoDB; EOG747PMG; -.
DR PhylomeDB; Q9Y4Z0; -.
DR Reactome; REACT_21257; Metabolism of RNA.
DR Reactome; REACT_71; Gene Expression.
DR ChiTaRS; LSM4; human.
DR GeneWiki; LSM4; -.
DR GenomeRNAi; 25804; -.
DR NextBio; 47015; -.
DR PRO; PR:Q9Y4Z0; -.
DR ArrayExpress; Q9Y4Z0; -.
DR Bgee; Q9Y4Z0; -.
DR CleanEx; HS_LSM4; -.
DR Genevestigator; Q9Y4Z0; -.
DR GO; GO:0005829; C:cytosol; TAS:Reactome.
DR GO; GO:0005681; C:spliceosomal complex; IEA:UniProtKB-KW.
DR GO; GO:0005688; C:U6 snRNP; TAS:ProtInc.
DR GO; GO:0003723; F:RNA binding; IEA:UniProtKB-KW.
DR GO; GO:0043928; P:exonucleolytic nuclear-transcribed mRNA catabolic process involved in deadenylation-dependent decay; TAS:Reactome.
DR GO; GO:0006397; P:mRNA processing; IEA:UniProtKB-KW.
DR GO; GO:0008380; P:RNA splicing; TAS:ProtInc.
DR InterPro; IPR027141; LSm4/Sm_D1/D3.
DR InterPro; IPR010920; LSM_dom.
DR InterPro; IPR001163; Ribonucl_LSM.
DR InterPro; IPR006649; Ribonucl_LSM_euk/arc.
DR PANTHER; PTHR23338; PTHR23338; 1.
DR Pfam; PF01423; LSM; 1.
DR SMART; SM00651; Sm; 1.
DR SUPFAM; SSF50182; SSF50182; 1.
PE 1: Evidence at protein level;
KW Acetylation; Complete proteome; Direct protein sequencing;
KW mRNA processing; mRNA splicing; Nucleus; Reference proteome;
KW Ribonucleoprotein; RNA-binding; Spliceosome.
FT CHAIN 1 139 U6 snRNA-associated Sm-like protein LSm4.
FT /FTId=PRO_0000125564.
FT MOD_RES 1 1 N-acetylmethionine.
SQ SEQUENCE 139 AA; 15350 MW; BCEFB20247335A1B CRC64;
MLPLSLLKTA QNHPMLVELK NGETYNGHLV SCDNWMNINL REVICTSRDG DKFWRMPECY
IRGSTIKYLR IPDEIIDMVK EEVVAKGRGR GGLQQQKQQK GRGMGGAGRG VFGGRGRGGI
PGTGRGQPEK KPGRQAGKQ
//
ID LSM4_HUMAN Reviewed; 139 AA.
AC Q9Y4Z0;
DT 01-DEC-2000, integrated into UniProtKB/Swiss-Prot.
read moreDT 01-NOV-1999, sequence version 1.
DT 22-JAN-2014, entry version 120.
DE RecName: Full=U6 snRNA-associated Sm-like protein LSm4;
DE AltName: Full=Glycine-rich protein;
DE Short=GRP;
GN Name=LSM4;
OS Homo sapiens (Human).
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini;
OC Catarrhini; Hominidae; Homo.
OX NCBI_TaxID=9606;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA].
RC TISSUE=Liver;
RX PubMed=10369684; DOI=10.1093/emboj/18.12.3451;
RA Salgado-Garrido J., Bragado-Nilsson E., Kandels-Lewis S., Seraphin B.;
RT "Sm and Sm-like proteins assemble in two related complexes of deep
RT evolutionary origin.";
RL EMBO J. 18:3451-3462(1999).
RN [2]
RP NUCLEOTIDE SEQUENCE [MRNA], AND PARTIAL PROTEIN SEQUENCE.
RX PubMed=10523320; DOI=10.1093/emboj/18.20.5789;
RA Achsel T., Brahms H., Kastner B., Bachi A., Wilm M., Luehrmann R.;
RT "A doughnut-shaped heteromer of human Sm-like proteins binds to the
RT 3'-end of U6 snRNA, thereby facilitating U4/U6 duplex formation in
RT vitro.";
RL EMBO J. 18:5789-5802(1999).
RN [3]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RC TISSUE=Hypothalamus;
RX PubMed=10931946; DOI=10.1073/pnas.160270997;
RA Hu R.-M., Han Z.-G., Song H.-D., Peng Y.-D., Huang Q.-H., Ren S.-X.,
RA Gu Y.-J., Huang C.-H., Li Y.-B., Jiang C.-L., Fu G., Zhang Q.-H.,
RA Gu B.-W., Dai M., Mao Y.-F., Gao G.-F., Rong R., Ye M., Zhou J.,
RA Xu S.-H., Gu J., Shi J.-X., Jin W.-R., Zhang C.-K., Wu T.-M.,
RA Huang G.-Y., Chen Z., Chen M.-D., Chen J.-L.;
RT "Gene expression profiling in the human hypothalamus-pituitary-adrenal
RT axis and full-length cDNA cloning.";
RL Proc. Natl. Acad. Sci. U.S.A. 97:9543-9548(2000).
RN [4]
RP NUCLEOTIDE SEQUENCE [MRNA].
RA Chan E.K.L.;
RL Submitted (APR-2000) to the EMBL/GenBank/DDBJ databases.
RN [5]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RC TISSUE=Lung;
RX PubMed=15489334; DOI=10.1101/gr.2596504;
RG The MGC Project Team;
RT "The status, quality, and expansion of the NIH full-length cDNA
RT project: the Mammalian Gene Collection (MGC).";
RL Genome Res. 14:2121-2127(2004).
RN [6]
RP PROTEIN SEQUENCE OF 1-20, ACETYLATION AT MET-1, AND MASS SPECTROMETRY.
RC TISSUE=Mammary carcinoma;
RA Bienvenut W.V., Matallanas D., Cooper W.N., Kolch W.;
RL Submitted (JUL-2007) to UniProtKB.
RN [7]
RP IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
RX PubMed=21269460; DOI=10.1186/1752-0509-5-17;
RA Burkard T.R., Planyavsky M., Kaupe I., Breitwieser F.P.,
RA Buerckstuemmer T., Bennett K.L., Superti-Furga G., Colinge J.;
RT "Initial characterization of the human central proteome.";
RL BMC Syst. Biol. 5:17-17(2011).
CC -!- FUNCTION: Binds specifically to the 3'-terminal U-tract of U6
CC snRNA.
CC -!- SUBUNIT: LSm subunits form a heteromer with a doughnut shape.
CC -!- INTERACTION:
CC Q9UK45:LSM7; NbExp=6; IntAct=EBI-372521, EBI-348372;
CC O95777:NAA38; NbExp=4; IntAct=EBI-372521, EBI-347779;
CC -!- SUBCELLULAR LOCATION: Nucleus (Potential).
CC -!- SIMILARITY: Belongs to the snRNP Sm proteins family.
CC -----------------------------------------------------------------------
CC Copyrighted by the UniProt Consortium, see http://www.uniprot.org/terms
CC Distributed under the Creative Commons Attribution-NoDerivs License
CC -----------------------------------------------------------------------
DR EMBL; AJ238096; CAB45867.1; -; mRNA.
DR EMBL; AF182290; AAD56228.1; -; mRNA.
DR EMBL; AF117235; AAF17216.1; -; mRNA.
DR EMBL; AF251218; AAF90055.1; -; mRNA.
DR EMBL; BC000387; AAH00387.1; -; mRNA.
DR EMBL; BC003652; AAH03652.1; -; mRNA.
DR EMBL; BC022198; AAH22198.1; -; mRNA.
DR EMBL; BC023665; AAH23665.1; -; mRNA.
DR RefSeq; NP_036453.1; NM_012321.4.
DR UniGene; Hs.515255; -.
DR ProteinModelPortal; Q9Y4Z0; -.
DR SMR; Q9Y4Z0; 14-71.
DR DIP; DIP-31209N; -.
DR IntAct; Q9Y4Z0; 16.
DR MINT; MINT-1469332; -.
DR STRING; 9606.ENSP00000252816; -.
DR PhosphoSite; Q9Y4Z0; -.
DR DMDM; 10720082; -.
DR PaxDb; Q9Y4Z0; -.
DR PeptideAtlas; Q9Y4Z0; -.
DR PRIDE; Q9Y4Z0; -.
DR DNASU; 25804; -.
DR Ensembl; ENST00000593829; ENSP00000469468; ENSG00000130520.
DR GeneID; 25804; -.
DR KEGG; hsa:25804; -.
DR UCSC; uc002niq.3; human.
DR CTD; 25804; -.
DR GeneCards; GC19M018417; -.
DR HGNC; HGNC:17259; LSM4.
DR HPA; HPA040932; -.
DR MIM; 607284; gene.
DR neXtProt; NX_Q9Y4Z0; -.
DR PharmGKB; PA134906569; -.
DR eggNOG; COG1958; -.
DR HOGENOM; HOG000182713; -.
DR HOVERGEN; HBG000486; -.
DR InParanoid; Q9Y4Z0; -.
DR KO; K12623; -.
DR OMA; GMQQQKQ; -.
DR OrthoDB; EOG747PMG; -.
DR PhylomeDB; Q9Y4Z0; -.
DR Reactome; REACT_21257; Metabolism of RNA.
DR Reactome; REACT_71; Gene Expression.
DR ChiTaRS; LSM4; human.
DR GeneWiki; LSM4; -.
DR GenomeRNAi; 25804; -.
DR NextBio; 47015; -.
DR PRO; PR:Q9Y4Z0; -.
DR ArrayExpress; Q9Y4Z0; -.
DR Bgee; Q9Y4Z0; -.
DR CleanEx; HS_LSM4; -.
DR Genevestigator; Q9Y4Z0; -.
DR GO; GO:0005829; C:cytosol; TAS:Reactome.
DR GO; GO:0005681; C:spliceosomal complex; IEA:UniProtKB-KW.
DR GO; GO:0005688; C:U6 snRNP; TAS:ProtInc.
DR GO; GO:0003723; F:RNA binding; IEA:UniProtKB-KW.
DR GO; GO:0043928; P:exonucleolytic nuclear-transcribed mRNA catabolic process involved in deadenylation-dependent decay; TAS:Reactome.
DR GO; GO:0006397; P:mRNA processing; IEA:UniProtKB-KW.
DR GO; GO:0008380; P:RNA splicing; TAS:ProtInc.
DR InterPro; IPR027141; LSm4/Sm_D1/D3.
DR InterPro; IPR010920; LSM_dom.
DR InterPro; IPR001163; Ribonucl_LSM.
DR InterPro; IPR006649; Ribonucl_LSM_euk/arc.
DR PANTHER; PTHR23338; PTHR23338; 1.
DR Pfam; PF01423; LSM; 1.
DR SMART; SM00651; Sm; 1.
DR SUPFAM; SSF50182; SSF50182; 1.
PE 1: Evidence at protein level;
KW Acetylation; Complete proteome; Direct protein sequencing;
KW mRNA processing; mRNA splicing; Nucleus; Reference proteome;
KW Ribonucleoprotein; RNA-binding; Spliceosome.
FT CHAIN 1 139 U6 snRNA-associated Sm-like protein LSm4.
FT /FTId=PRO_0000125564.
FT MOD_RES 1 1 N-acetylmethionine.
SQ SEQUENCE 139 AA; 15350 MW; BCEFB20247335A1B CRC64;
MLPLSLLKTA QNHPMLVELK NGETYNGHLV SCDNWMNINL REVICTSRDG DKFWRMPECY
IRGSTIKYLR IPDEIIDMVK EEVVAKGRGR GGLQQQKQQK GRGMGGAGRG VFGGRGRGGI
PGTGRGQPEK KPGRQAGKQ
//
MIM
607284
*RECORD*
*FIELD* NO
607284
*FIELD* TI
*607284 LSM4 PROTEIN; LSM4
*FIELD* TX
DESCRIPTION
Sm-like proteins were identified in a variety of organisms based on
read moresequence homology with the Sm protein family (see SNRPD2; 601061).
Sm-like proteins contain the Sm sequence motif, which consists of 2
regions separated by a linker of variable length that folds as a loop.
The Sm-like proteins are thought to form a stable heteromer present in
tri-snRNP particles, which are important for pre-mRNA splicing.
CLONING
In a search for human Sm-like proteins, Achsel et al. (1999)
fractionated proteins present in purified (U4/U6.U5) tri-snRNPs and
isolated 7 Sm-like proteins, which they named LSm2-LSm8. Using partial
peptide sequence for database searches, they identified and sequenced
EST clones. Using additional sequence obtained by PCR amplification of a
HeLa cDNA library, they assembled full-length cDNA sequences for
LSM2-LSM8.
Salgado-Garrido et al. (1999) searched database sequence for Sm proteins
and identified 16 potential Sm-related genes in yeast as well as some
Sm-related genes in human and archaebacteria. Using a multiple sequence
alignment of Sm domains, they built a phylogenetic tree of yeast, human,
and archaeal Sm and Sm-like proteins.
GENE FUNCTION
Using electron-microscopy, Achsel et al. (1999) observed that purified
LSm proteins form a heteromer that is stable even in the absence of RNA
and exhibits a doughnut-shaped structure similar to the Sm core RNP
structure. They demonstrated that the purified LSm heteromer binds
specifically to the U6 snRNA at its 3-prime-terminal U-tract. They also
showed that the LSm proteins facilitate the formation of U4/U6 RNA
duplexes in vitro and concluded that the LSm proteins may play a role in
U4/U6 snRNP formation.
Using immunoprecipitation experiments, Salgado-Garrido et al. (1999)
concluded that there is a complex of 7 Sm-like proteins bound to RNA in
yeast. Lsm2-Lsm8 coprecipitate the U4, U5 and U6 snRNAs and directly
associate with the U6 snRNA present in the free U6 snRNP. Additionally,
the yeast Lsm2-Lsm7 proteins were found to be associated with the
pre-RNase P RNA but not the mature RNase RNA. Using immunoprecipitation
experiments from human cell extracts, Salgado-Garrido et al. (1999)
showed that the LSM3 and LSM4 proteins are specifically associated with
snRNP complexes containing the U6 snRNA. Salgado-Garrido et al. (1999)
concluded that Sm and Sm-like proteins assemble in at least 2
functionally conserved complexes of deep evolutionary origin.
By disrupting the Sm and Sm-like genes in yeast, Salgado-Garrido et al.
(1999) concluded that disruption of genes encoding Sm-like proteins
directly associated with the U6 snRNA (Lsm2-8) generated variable
phenotypes. Lsm2, Lsm3, Lsm4, and Lsm8 are essential for vegetative
growth. Lsm5, Lsm6, and Lsm7 are not essential for growth; however,
their disruptions lead to slow growth especially at elevated
temperature. The levels of the U6 snRNA were strongly reduced in the
strains harboring the Lsm5, Lsm6, and Lsm7 disruptions. Lsm1 and Lsm9
are dispensable for vegetative growth, but Lsm1 is required for optimal
vegetative growth at 30 degrees and is temperature sensitive.
Ingelfinger et al. (2002) determined that human LSM1 to LSM7, but not
LSM8, were expressed in HeLa cells within cytoplasmic foci. The foci
also contained a decapping enzyme (DCP1/2) and the exonuclease XRN1
(607994). Coexpression of wildtype and mutant LSM proteins, as well as
fluorescence resonance energy transfer, indicated that the LSM proteins
form a complex similar to one found in yeast. Ingelfinger et al. (2002)
concluded that the foci contain a partially or fully assembled machinery
for the degradation of mRNA.
MAPPING
The International Radiation Hybrid Mapping Consortium mapped the LSM4
gene to chromosome 19 (TMAP stSG3964).
*FIELD* RF
1. Achsel, T.; Brahms, H.; Kastner, B.; Bachi, A.; Wilm, M.; Luhrmann,
R.: A doughnut-shaped heteromer of human Sm-like proteins binds to
the 3-prime end of U6 snRNA, thereby facilitating U4/U6 duplex formation
in vitro. EMBO J. 18: 5789-5802, 1999.
2. Ingelfinger, D.; Arndt-Jovin, D. J.; Luhrmann, R.; Achsel, T.:
The human LSm1-7 proteins colocalize with the mRNA-degrading enzymes
Dcp1/2 and Xrn1 in distinct cytoplasmic foci. RNA 8: 1489-1501,
2002.
3. Salgado-Garrido, J.; Bragado-Nilsson, E.; Kandels-Lewis, S.; Seraphin,
B.: Sm and Sm-like proteins assemble in two related complexes of
deep evolutionary origin. EMBO J. 18: 3451-3462, 1999.
*FIELD* CN
Patricia A. Hartz - updated: 7/29/2003
*FIELD* CD
Dawn Watkins-Chow: 10/9/2002
*FIELD* ED
alopez: 03/08/2005
mgross: 7/29/2003
carol: 10/9/2002
*RECORD*
*FIELD* NO
607284
*FIELD* TI
*607284 LSM4 PROTEIN; LSM4
*FIELD* TX
DESCRIPTION
Sm-like proteins were identified in a variety of organisms based on
read moresequence homology with the Sm protein family (see SNRPD2; 601061).
Sm-like proteins contain the Sm sequence motif, which consists of 2
regions separated by a linker of variable length that folds as a loop.
The Sm-like proteins are thought to form a stable heteromer present in
tri-snRNP particles, which are important for pre-mRNA splicing.
CLONING
In a search for human Sm-like proteins, Achsel et al. (1999)
fractionated proteins present in purified (U4/U6.U5) tri-snRNPs and
isolated 7 Sm-like proteins, which they named LSm2-LSm8. Using partial
peptide sequence for database searches, they identified and sequenced
EST clones. Using additional sequence obtained by PCR amplification of a
HeLa cDNA library, they assembled full-length cDNA sequences for
LSM2-LSM8.
Salgado-Garrido et al. (1999) searched database sequence for Sm proteins
and identified 16 potential Sm-related genes in yeast as well as some
Sm-related genes in human and archaebacteria. Using a multiple sequence
alignment of Sm domains, they built a phylogenetic tree of yeast, human,
and archaeal Sm and Sm-like proteins.
GENE FUNCTION
Using electron-microscopy, Achsel et al. (1999) observed that purified
LSm proteins form a heteromer that is stable even in the absence of RNA
and exhibits a doughnut-shaped structure similar to the Sm core RNP
structure. They demonstrated that the purified LSm heteromer binds
specifically to the U6 snRNA at its 3-prime-terminal U-tract. They also
showed that the LSm proteins facilitate the formation of U4/U6 RNA
duplexes in vitro and concluded that the LSm proteins may play a role in
U4/U6 snRNP formation.
Using immunoprecipitation experiments, Salgado-Garrido et al. (1999)
concluded that there is a complex of 7 Sm-like proteins bound to RNA in
yeast. Lsm2-Lsm8 coprecipitate the U4, U5 and U6 snRNAs and directly
associate with the U6 snRNA present in the free U6 snRNP. Additionally,
the yeast Lsm2-Lsm7 proteins were found to be associated with the
pre-RNase P RNA but not the mature RNase RNA. Using immunoprecipitation
experiments from human cell extracts, Salgado-Garrido et al. (1999)
showed that the LSM3 and LSM4 proteins are specifically associated with
snRNP complexes containing the U6 snRNA. Salgado-Garrido et al. (1999)
concluded that Sm and Sm-like proteins assemble in at least 2
functionally conserved complexes of deep evolutionary origin.
By disrupting the Sm and Sm-like genes in yeast, Salgado-Garrido et al.
(1999) concluded that disruption of genes encoding Sm-like proteins
directly associated with the U6 snRNA (Lsm2-8) generated variable
phenotypes. Lsm2, Lsm3, Lsm4, and Lsm8 are essential for vegetative
growth. Lsm5, Lsm6, and Lsm7 are not essential for growth; however,
their disruptions lead to slow growth especially at elevated
temperature. The levels of the U6 snRNA were strongly reduced in the
strains harboring the Lsm5, Lsm6, and Lsm7 disruptions. Lsm1 and Lsm9
are dispensable for vegetative growth, but Lsm1 is required for optimal
vegetative growth at 30 degrees and is temperature sensitive.
Ingelfinger et al. (2002) determined that human LSM1 to LSM7, but not
LSM8, were expressed in HeLa cells within cytoplasmic foci. The foci
also contained a decapping enzyme (DCP1/2) and the exonuclease XRN1
(607994). Coexpression of wildtype and mutant LSM proteins, as well as
fluorescence resonance energy transfer, indicated that the LSM proteins
form a complex similar to one found in yeast. Ingelfinger et al. (2002)
concluded that the foci contain a partially or fully assembled machinery
for the degradation of mRNA.
MAPPING
The International Radiation Hybrid Mapping Consortium mapped the LSM4
gene to chromosome 19 (TMAP stSG3964).
*FIELD* RF
1. Achsel, T.; Brahms, H.; Kastner, B.; Bachi, A.; Wilm, M.; Luhrmann,
R.: A doughnut-shaped heteromer of human Sm-like proteins binds to
the 3-prime end of U6 snRNA, thereby facilitating U4/U6 duplex formation
in vitro. EMBO J. 18: 5789-5802, 1999.
2. Ingelfinger, D.; Arndt-Jovin, D. J.; Luhrmann, R.; Achsel, T.:
The human LSm1-7 proteins colocalize with the mRNA-degrading enzymes
Dcp1/2 and Xrn1 in distinct cytoplasmic foci. RNA 8: 1489-1501,
2002.
3. Salgado-Garrido, J.; Bragado-Nilsson, E.; Kandels-Lewis, S.; Seraphin,
B.: Sm and Sm-like proteins assemble in two related complexes of
deep evolutionary origin. EMBO J. 18: 3451-3462, 1999.
*FIELD* CN
Patricia A. Hartz - updated: 7/29/2003
*FIELD* CD
Dawn Watkins-Chow: 10/9/2002
*FIELD* ED
alopez: 03/08/2005
mgross: 7/29/2003
carol: 10/9/2002