The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) i ...
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) in common, which assemble around the Sm site present in four of the major spliceosomal small nuclear RNAs. The U6 snRNP binds to the LSM (Like Sm) proteins [3]. Sm proteins are also found in archaebacteria, which do not have any splicing apparatus suggesting a more general role for Sm proteins. All Sm proteins contain a common sequence motif in two segments, Sm1 and Sm2, separated by a short variable linker. This family also includes the bacterial Hfq (host factor Q) proteins. Hfq are also RNA-binding proteins, that form hexameric rings.
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) i ...
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) in common, which assemble around the Sm site present in four of the major spliceosomal small nuclear RNAs. The U6 snRNP binds to the LSM (Like Sm) proteins [3]. Sm proteins are also found in archaebacteria, which do not have any splicing apparatus suggesting a more general role for Sm proteins. All Sm proteins contain a common sequence motif in two segments, Sm1 and Sm2, separated by a short variable linker. This family also includes the bacterial Hfq (host factor Q) proteins. Hfq are also RNA-binding proteins, that form hexameric rings.
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) i ...
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) in common, which assemble around the Sm site present in four of the major spliceosomal small nuclear RNAs. The U6 snRNP binds to the LSM (Like Sm) proteins [3]. Sm proteins are also found in archaebacteria, which do not have any splicing apparatus suggesting a more general role for Sm proteins. All Sm proteins contain a common sequence motif in two segments, Sm1 and Sm2, separated by a short variable linker. This family also includes the bacterial Hfq (host factor Q) proteins. Hfq are also RNA-binding proteins, that form hexameric rings.
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) i ...
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) in common, which assemble around the Sm site present in four of the major spliceosomal small nuclear RNAs. The U6 snRNP binds to the LSM (Like Sm) proteins [3]. Sm proteins are also found in archaebacteria, which do not have any splicing apparatus suggesting a more general role for Sm proteins. All Sm proteins contain a common sequence motif in two segments, Sm1 and Sm2, separated by a short variable linker. This family also includes the bacterial Hfq (host factor Q) proteins. Hfq are also RNA-binding proteins, that form hexameric rings.
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) i ...
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) in common, which assemble around the Sm site present in four of the major spliceosomal small nuclear RNAs. The U6 snRNP binds to the LSM (Like Sm) proteins [3]. Sm proteins are also found in archaebacteria, which do not have any splicing apparatus suggesting a more general role for Sm proteins. All Sm proteins contain a common sequence motif in two segments, Sm1 and Sm2, separated by a short variable linker. This family also includes the bacterial Hfq (host factor Q) proteins. Hfq are also RNA-binding proteins, that form hexameric rings.
The RRM motif (a.k.a. RRM, RBD, or RNP domain) is probably diagnostic of an RNA binding protein. RRMs are found in a variety of RNA binding proteins, including various hnRNP proteins, proteins implicated in regulation of alternative splicing, and pro ...
The RRM motif (a.k.a. RRM, RBD, or RNP domain) is probably diagnostic of an RNA binding protein. RRMs are found in a variety of RNA binding proteins, including various hnRNP proteins, proteins implicated in regulation of alternative splicing, and protein components of snRNPs. The motif also appears in a few single stranded DNA binding proteins. The RRM structure consists of four strands and two helices arranged in an alpha/beta sandwich, with a third helix present during RNA binding in some cases The C-terminal beta strand (4th strand) and final helix are hard to align and have been omitted in the SEED alignment The LA proteins (Swiss:P05455) have an N terminal rrm which is included in the seed. There is a second region towards the C terminus that has some features characteristic of a rrm but does not appear to have the important structural core of a rrm. The LA proteins (Swiss:P05455) are one of the main autoantigens in Systemic lupus erythematosus (SLE), an autoimmune disease.
This entry represents the N-terminal domain of STL11 from yeast and its homologues [1-4], such as RBM22 from human. This domain comprises a zinc finger, FYVE/PHD type. Members of this entry are involved in pre-mRNA splicing.
The RRM motif (a.k.a. RRM, RBD, or RNP domain) is probably diagnostic of an RNA binding protein. RRMs are found in a variety of RNA binding proteins, including various hnRNP proteins, proteins implicated in regulation of alternative splicing, and pro ...
The RRM motif (a.k.a. RRM, RBD, or RNP domain) is probably diagnostic of an RNA binding protein. RRMs are found in a variety of RNA binding proteins, including various hnRNP proteins, proteins implicated in regulation of alternative splicing, and protein components of snRNPs. The motif also appears in a few single stranded DNA binding proteins. The RRM structure consists of four strands and two helices arranged in an alpha/beta sandwich, with a third helix present during RNA binding in some cases The C-terminal beta strand (4th strand) and final helix are hard to align and have been omitted in the SEED alignment The LA proteins (Swiss:P05455) have an N terminal rrm which is included in the seed. There is a second region towards the C terminus that has some features characteristic of a rrm but does not appear to have the important structural core of a rrm. The LA proteins (Swiss:P05455) are one of the main autoantigens in Systemic lupus erythematosus (SLE), an autoimmune disease.
This entry represents the insert domain of intron-binding protein aquarius, a splicing factor which links excision of introns from pre-mRNA with snoRP assembly [1,2].
This family of domains contain a P-loop motif that is characteristic of the AAA superfamily. Many of the proteins in this family are conjugative transfer proteins.
This entry represents the beta-barrel domain found at the N-terminal of intron-binding protein aquarius, a splicing factor which links excision of introns from pre-mRNA with snoRP assembly [1,2].
This family of domains contain a P-loop motif that is characteristic of the AAA superfamily. Many of the proteins in this family are conjugative transfer proteins.
This regions is found specifically in PRP19-like protein. The region represented by this family covers the sequence implicated in self-interaction and a coiled-coiled motif [1]. PRP19-like proteins form an oligomer that is necessary for spliceosome ...
This regions is found specifically in PRP19-like protein. The region represented by this family covers the sequence implicated in self-interaction and a coiled-coiled motif [1]. PRP19-like proteins form an oligomer that is necessary for spliceosome assembly [1].
The U-box is a domain of ~70 amino acids that is present in proteins from yeast to human. It consists of the beta-beta-alpha-beta-alpha- fold typical of U-box and RING domains. The central alpha helix is flanked by two prominent surface-exposed loop ...
The U-box is a domain of ~70 amino acids that is present in proteins from yeast to human. It consists of the beta-beta-alpha-beta-alpha- fold typical of U-box and RING domains. The central alpha helix is flanked by two prominent surface-exposed loop regions. This domain is one class of E3 ligases, involved in the ubiquitination process [1-3]. This domain is related to the Ring finger Pfam:PF00097 but lacks the zinc binding residues [4].
This regions is found specifically in PRP19-like protein. The region represented by this family covers the sequence implicated in self-interaction and a coiled-coiled motif [1]. PRP19-like proteins form an oligomer that is necessary for spliceosome ...
This regions is found specifically in PRP19-like protein. The region represented by this family covers the sequence implicated in self-interaction and a coiled-coiled motif [1]. PRP19-like proteins form an oligomer that is necessary for spliceosome assembly [1].
The U-box is a domain of ~70 amino acids that is present in proteins from yeast to human. It consists of the beta-beta-alpha-beta-alpha- fold typical of U-box and RING domains. The central alpha helix is flanked by two prominent surface-exposed loop ...
The U-box is a domain of ~70 amino acids that is present in proteins from yeast to human. It consists of the beta-beta-alpha-beta-alpha- fold typical of U-box and RING domains. The central alpha helix is flanked by two prominent surface-exposed loop regions. This domain is one class of E3 ligases, involved in the ubiquitination process [1-3]. This domain is related to the Ring finger Pfam:PF00097 but lacks the zinc binding residues [4].
Cyclophilin type peptidyl-prolyl cis-trans isomerase/CLD
The peptidyl-prolyl cis-trans isomerases, also known as cyclophilins, share this domain of about 109 amino acids. Cyclophilins have been found in all organisms studied so far and catalyse peptidyl-prolyl isomerisation during which the peptide bond pr ...
The peptidyl-prolyl cis-trans isomerases, also known as cyclophilins, share this domain of about 109 amino acids. Cyclophilins have been found in all organisms studied so far and catalyse peptidyl-prolyl isomerisation during which the peptide bond preceding proline (the peptidyl-prolyl bond) is stabilised in the cis conformation. Mammalian cyclophilin A (CypA) is a major cellular target for the immunosuppressive drug cyclosporin A (CsA). Other roles for cyclophilins may include chaperone and cell signalling function [1].
This regions is found specifically in PRP19-like protein. The region represented by this family covers the sequence implicated in self-interaction and a coiled-coiled motif [1]. PRP19-like proteins form an oligomer that is necessary for spliceosome ...
This regions is found specifically in PRP19-like protein. The region represented by this family covers the sequence implicated in self-interaction and a coiled-coiled motif [1]. PRP19-like proteins form an oligomer that is necessary for spliceosome assembly [1].
The U-box is a domain of ~70 amino acids that is present in proteins from yeast to human. It consists of the beta-beta-alpha-beta-alpha- fold typical of U-box and RING domains. The central alpha helix is flanked by two prominent surface-exposed loop ...
The U-box is a domain of ~70 amino acids that is present in proteins from yeast to human. It consists of the beta-beta-alpha-beta-alpha- fold typical of U-box and RING domains. The central alpha helix is flanked by two prominent surface-exposed loop regions. This domain is one class of E3 ligases, involved in the ubiquitination process [1-3]. This domain is related to the Ring finger Pfam:PF00097 but lacks the zinc binding residues [4].
This regions is found specifically in PRP19-like protein. The region represented by this family covers the sequence implicated in self-interaction and a coiled-coiled motif [1]. PRP19-like proteins form an oligomer that is necessary for spliceosome ...
This regions is found specifically in PRP19-like protein. The region represented by this family covers the sequence implicated in self-interaction and a coiled-coiled motif [1]. PRP19-like proteins form an oligomer that is necessary for spliceosome assembly [1].
The U-box is a domain of ~70 amino acids that is present in proteins from yeast to human. It consists of the beta-beta-alpha-beta-alpha- fold typical of U-box and RING domains. The central alpha helix is flanked by two prominent surface-exposed loop ...
The U-box is a domain of ~70 amino acids that is present in proteins from yeast to human. It consists of the beta-beta-alpha-beta-alpha- fold typical of U-box and RING domains. The central alpha helix is flanked by two prominent surface-exposed loop regions. This domain is one class of E3 ligases, involved in the ubiquitination process [1-3]. This domain is related to the Ring finger Pfam:PF00097 but lacks the zinc binding residues [4].
The essential spliceosomal protein Prp8 interacts with U5 and U6 snRNAs and with specific pre-mRNA sequences that participate in catalysis [1]. This close association with crucial RNA sequences, together with extensive genetic evidence, suggests that ...
The essential spliceosomal protein Prp8 interacts with U5 and U6 snRNAs and with specific pre-mRNA sequences that participate in catalysis [1]. This close association with crucial RNA sequences, together with extensive genetic evidence, suggests that Prp8 could directly affect the function of the catalytic core, perhaps acting as a splicing cofactor [2].
The large RNA-protein complex of the spliceosome catalyses pre-mRNA splicing. One of the most conserved core proteins is PrP8 which occupies a central position in the catalytic core of the spliceosome, and has been implicated in several crucial molec ...
The large RNA-protein complex of the spliceosome catalyses pre-mRNA splicing. One of the most conserved core proteins is PrP8 which occupies a central position in the catalytic core of the spliceosome, and has been implicated in several crucial molecular rearrangements that occur there, and has recently come under the spotlight for its role in the inherited human disease, Retinitis Pigmentosa [1]. The RNA-recognition motif of PrP8 is highly conserved and provides a possible RNA binding centre for the 5-prime SS, BP, or 3-prime SS of pre-mRNA which are known to contact with Prp8. The most conserved regions of an RRM are defined as the RNP1 and RNP2 sequences. Recognition of RNA targets can also be modulated by a number of other factors, most notably the two loops beta1-alpha1, beta2-beta3 and the amino acid residues C-terminal to the RNP2 domain [2].
This domain incorporates the interacting site for the U6-snRNA as part of the U4/U6.U5 tri-snRNPs complex of the spliceosome, and is the prime candidate for the role of cofactor for the spliceosome's RNA core. The essential spliceosomal protein Prp8 ...
This domain incorporates the interacting site for the U6-snRNA as part of the U4/U6.U5 tri-snRNPs complex of the spliceosome, and is the prime candidate for the role of cofactor for the spliceosome's RNA core. The essential spliceosomal protein Prp8 interacts with U5 and U6 snRNAs and with specific pre-mRNA sequences that participate in catalysis. This close association with crucial RNA sequences, together with extensive genetic evidence, suggests that Prp8 could directly affect the function of the catalytic core, perhaps acting as a splicing cofactor [1].
The PRO8NT domain is found at the N-terminus of pre-mRNA splicing factors of PRO8 family [1]. The NLS or nuclear localisation signal for these spliceosome proteins begins at the start and runs for 60 residues. N-terminal to this domain is a highly va ...
The PRO8NT domain is found at the N-terminus of pre-mRNA splicing factors of PRO8 family [1]. The NLS or nuclear localisation signal for these spliceosome proteins begins at the start and runs for 60 residues. N-terminal to this domain is a highly variable proline-rich region [4].
Proteins with this domain are found in proteasome regulatory subunits, eukaryotic initiation factor 3 (eIF3) subunits and regulators of transcription factors. This domain is known as the MPN domain [3] and PAD-1-like domain [4], JABP1 domain [5] or J ...
Proteins with this domain are found in proteasome regulatory subunits, eukaryotic initiation factor 3 (eIF3) subunits and regulators of transcription factors. This domain is known as the MPN domain [3] and PAD-1-like domain [4], JABP1 domain [5] or JAMM domain [7]. These are metalloenzymes that function as the ubiquitin isopeptidase/ deubiquitinase in the ubiquitin-based signalling and protein turnover pathways in eukaryotes [7]. Versions of the domain in prokaryotic cognates of the ubiquitin-modification pathway are shown to have a similar role, and the archaeal protein from Haloferax volcanii is found to cleave ubiquitin-like small archaeal modifier proteins (SAMP1/2) from protein conjugates [8,9].
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) i ...
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) in common, which assemble around the Sm site present in four of the major spliceosomal small nuclear RNAs. The U6 snRNP binds to the LSM (Like Sm) proteins [3]. Sm proteins are also found in archaebacteria, which do not have any splicing apparatus suggesting a more general role for Sm proteins. All Sm proteins contain a common sequence motif in two segments, Sm1 and Sm2, separated by a short variable linker. This family also includes the bacterial Hfq (host factor Q) proteins. Hfq are also RNA-binding proteins, that form hexameric rings.
This entry represents the Plug domain from the Brr2 RNA helicase protein. The Brr2 helicase provides the key remodelling activity for spliceosome catalytic activation, during which it disrupts the U4/U6 di-snRNP (small nuclear RNA protein) [2]. The p ...
This entry represents the Plug domain from the Brr2 RNA helicase protein. The Brr2 helicase provides the key remodelling activity for spliceosome catalytic activation, during which it disrupts the U4/U6 di-snRNP (small nuclear RNA protein) [2]. The plug domain is a small alpha helical bundle domain found near the N-terminus of the Brr2 protein [2].
Members of this family include the DEAD and DEAH box helicases. Helicases are involved in unwinding nucleic acids. The DEAD box helicases are involved in various aspects of RNA metabolism, including nuclear transcription, pre mRNA splicing, ribosome ...
Members of this family include the DEAD and DEAH box helicases. Helicases are involved in unwinding nucleic acids. The DEAD box helicases are involved in various aspects of RNA metabolism, including nuclear transcription, pre mRNA splicing, ribosome biogenesis, nucleocytoplasmic transport, translation, RNA decay and organellar gene expression.
The Prosite family is restricted to DEAD/H helicases, whereas this domain family is found in a wide variety of helicases and helicase related proteins. It may be that this is not an autonomously folding unit, but an integral part of the helicase.
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) i ...
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) in common, which assemble around the Sm site present in four of the major spliceosomal small nuclear RNAs. The U6 snRNP binds to the LSM (Like Sm) proteins [3]. Sm proteins are also found in archaebacteria, which do not have any splicing apparatus suggesting a more general role for Sm proteins. All Sm proteins contain a common sequence motif in two segments, Sm1 and Sm2, separated by a short variable linker. This family also includes the bacterial Hfq (host factor Q) proteins. Hfq are also RNA-binding proteins, that form hexameric rings.
This domain includes the carboxyl terminal regions of Elongation factor G, elongation factor 2 and some tetracycline resistance proteins and adopt a ferredoxin-like fold.
This domain contains a P-loop motif, also found in several other families such as Pfam:PF00071, Pfam:PF00025 and Pfam:PF00063. Elongation factor Tu consists of three structural domains, this plus two C-terminal beta barrel domains.
Elongation factor Tu consists of three structural domains, this is the second domain. This domain adopts a beta barrel structure. This the second domain is involved in binding to charged tRNA [1]. This domain is also found in other proteins such as e ...
Elongation factor Tu consists of three structural domains, this is the second domain. This domain adopts a beta barrel structure. This the second domain is involved in binding to charged tRNA [1]. This domain is also found in other proteins such as elongation factor G and translation initiation factor IF-2. This domain is structurally related to Pfam:PF03143, and in fact has weak sequence matches to this domain.
This domain is found in elongation factor G, elongation factor 2 and some tetracycline resistance proteins and adopts a ribosomal protein S5 domain 2-like fold.
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) i ...
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) in common, which assemble around the Sm site present in four of the major spliceosomal small nuclear RNAs. The U6 snRNP binds to the LSM (Like Sm) proteins [3]. Sm proteins are also found in archaebacteria, which do not have any splicing apparatus suggesting a more general role for Sm proteins. All Sm proteins contain a common sequence motif in two segments, Sm1 and Sm2, separated by a short variable linker. This family also includes the bacterial Hfq (host factor Q) proteins. Hfq are also RNA-binding proteins, that form hexameric rings.
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) i ...
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) in common, which assemble around the Sm site present in four of the major spliceosomal small nuclear RNAs. The U6 snRNP binds to the LSM (Like Sm) proteins [3]. Sm proteins are also found in archaebacteria, which do not have any splicing apparatus suggesting a more general role for Sm proteins. All Sm proteins contain a common sequence motif in two segments, Sm1 and Sm2, separated by a short variable linker. This family also includes the bacterial Hfq (host factor Q) proteins. Hfq are also RNA-binding proteins, that form hexameric rings.
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) i ...
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) in common, which assemble around the Sm site present in four of the major spliceosomal small nuclear RNAs. The U6 snRNP binds to the LSM (Like Sm) proteins [3]. Sm proteins are also found in archaebacteria, which do not have any splicing apparatus suggesting a more general role for Sm proteins. All Sm proteins contain a common sequence motif in two segments, Sm1 and Sm2, separated by a short variable linker. This family also includes the bacterial Hfq (host factor Q) proteins. Hfq are also RNA-binding proteins, that form hexameric rings.
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) i ...
The LSM domain contains Sm proteins as well as other related LSM (Like Sm) proteins. The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B', D1, D2, D3, E, F and G) in common, which assemble around the Sm site present in four of the major spliceosomal small nuclear RNAs. The U6 snRNP binds to the LSM (Like Sm) proteins [3]. Sm proteins are also found in archaebacteria, which do not have any splicing apparatus suggesting a more general role for Sm proteins. All Sm proteins contain a common sequence motif in two segments, Sm1 and Sm2, separated by a short variable linker. This family also includes the bacterial Hfq (host factor Q) proteins. Hfq are also RNA-binding proteins, that form hexameric rings.
