Sterile alpha motif is a putative protein interaction module present in a wide variety of proteins involved in many biological processes. The SAM domain that spreads over around 70 residues is found in diverse eukaryotic organisms. SAM domains have been shown to homo- and hetero-oligomerise, forming multiple self-association architectures and also binding to various non-SAM domain-containing proteins, nevertheless with a low affinity constant.

SAM domains also appear to possess the ability to bind RNA

RNA

Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

. Smaug a protein that helps to establish a morphogen gradient in Drosophila embryos by repressing the translation of nanos (nos) mRNA

Nanos 3' UTR translation control element

Nanos 3' UTR translation control element is a cis-regulatory element in the 3' untranslated region of the messenger RNA which encodes the Nanos protein. The Nanos protein in Drosophila is required for correct morphogenesis in the Drosophila embryo...

 binds to the 3' untranslated region (UTR) of nos mRNA via two similar hairpin structures. The 3D crystal structure of the Smaug RNA-binding region shows a cluster of positively charged residues on the Smaug-SAM domain, which could be the RNA-binding surface. This electropositive potential is unique among all previously determined SAM-domain structures and is conserved among Smaug-SAM homologs. These results suggest that the SAM domain might have a primary role in RNA binding.

Structural analyses show that the SAM domain is arranged in a small five-helix bundle with two large interfaces. In the case of the SAM domain of EPHB2, each of these interfaces is able to form dimers. The presence of these two distinct intermonomers binding surface suggest that SAM could form extended polymeric structures.

Human proteins containing this domain

ANKS1A

ANKS1A

Ankyrin repeat and SAM domain-containing protein 1A is a protein that in humans is encoded by the ANKS1A gene.-Further reading:...

; ANKS1B

ANKS1B

Ankyrin repeat and sterile alpha motif domain-containing protein 1B is a protein that in humans is encoded by the ANKS1B gene.-Further reading:...

; ANKS3; ANKS4B; ANKS6; BFAR; BICC1; CASKIN1;
CASKIN2; CENTD1

CENTD1

Arf-GAP with Rho-GAP domain, ANK repeat and PH domain-containing protein 2 is a protein that in humans is encoded by the ARAP2 gene.-Further reading:...

; CNKSR2

CNKSR2

Connector enhancer of kinase suppressor of ras 2, also known as CNK homolog protein 2 or maguin , is an enzyme that in humans is encoded by the CNKSR2 gene.- Function :...

; CNKSR3; DDHD2; EPHA1

EPHA1

EPH receptor A1 is a protein that in humans is encoded by the EPHA1 gene.-Further reading:...

; EPHA10; EPHA2;
EPHA5

EPHA5

EPH receptor A5 is a protein that in humans is encoded by the EPHA5 gene.-Further reading:...

; EPHA6

EPHA6

Ephrin type-A receptor 6 is a protein that in humans is encoded by the EPHA6 gene.-Further reading:...

; EPHA7

EPHA7

Ephrin type-A receptor 7 is a protein that in humans is encoded by the EPHA7 gene.-Further reading:...

; EPHA8

EPHA8

Ephrin type-A receptor 8 is a protein that in humans is encoded by the EPHA8 gene.-Further reading:...

; EPHB1; EPHB2; EPHB3

EPHB3

Ephrin type-B receptor 3 is a protein that in humans is encoded by the EPHB3 gene.-Interactions:EPHB3 has been shown to interact with MLLT4 and RAS p21 protein activator 1.-Further reading:...

; EPHB4;
FAM59A; HPH2; INPPL1

INPPL1

Phosphatidylinositol-3,4,5-trisphosphate 5-phosphatase 2 is an enzyme that in humans is encoded by the INPPL1 gene.-Interactions:INPPL1 has been shown to interact with BCAR1, SORBS1, FLNC and SHC1.-Further reading:...

; L3MBTL3; PHC1

PHC1

Polyhomeotic-like protein 1 is a protein that in humans is encoded by the PHC1 gene.-Interactions:PHC1 has been shown to interact with BMI1 and PHC2.-Further reading:...

; PHC2

PHC2

Polyhomeotic-like protein 2 is a protein that in humans is encoded by the PHC2 gene.-Interactions:PHC2 has been shown to interact with MAPKAPK2, PHC1, BMI1 and MCRS1.-Further reading:...

; PHC3

PHC3

Polyhomeotic-like protein 3 is a protein that in humans is encoded by the PHC3 gene.-Further reading:...

; PPFIA1

PPFIA1

Liprin-alpha-1 is a protein that in humans is encoded by the PPFIA1 gene.-Interactions:Protein tyrosine phosphatase, receptor type, f polypeptide , interacting protein , alpha 1 has been shown to interact with PTPRF, GRIP2, PTPRD, PPP2R5D, PPFIBP1, PTPRS, ERC2 and GIT1.-Further reading:...

;
PPFIA2; PPFIA3; PPFIA4

PPFIA4

Liprin-alpha-4 is a protein that in humans is encoded by the PPFIA4 gene.-Interactions:PPFIA4 has been shown to interact with ERC2, GIT1 and Nuclear receptor coactivator 2.-Further reading:...

; PPFIBP1

PPFIBP1

Liprin-beta-1 is a protein that in humans is encoded by the PPFIBP1 gene.-Interactions:PPFIBP1 has been shown to interact with liprin-alpha-1.-Further reading:...

; PPFIBP2; SAMD1; SAMD13; SAMD14;
SAMD3; SAMD4A; SAMD4B; SAMD5; SAMD7; SAMD8; SAMD9

SAMD9

Sterile alpha motif domain-containing protein 9 is a protein that in humans is encoded by the SAMD9 gene.-Further reading:...

; SCMH1

SCMH1

Polycomb protein SCMH1 is a protein that in humans is encoded by the SCMH1 gene.-Further reading:...

;
SCML1; SCML2; SEC23IP

SEC23IP

SEC23-interacting protein is a protein that in humans is encoded by the SEC23IP gene.-Further reading:...

; SGMS1

SGMS1

Phosphatidylcholine:ceramide cholinephosphotransferase 1 is an enzyme that in humans is encoded by the SGMS1 gene.-Further reading:...

; SHANK1

SHANK1

SH3 and multiple ankyrin repeat domains protein 1 is a protein that in humans is encoded by the SHANK1 gene.-Interactions:SHANK1 has been shown to interact with SPTAN1, BAIAP2, ARHGEF7, DNM2 and Somatostatin receptor 2.-Further reading:...

; SHANK2

SHANK2

SH3 and multiple ankyrin repeat domains protein 2 is a protein that in humans is encoded by the SHANK2 gene. Two alternative splice variants, encoding distinct isoforms, are reported...

; SHANK3

SHANK3

SH3 and multiple ankyrin repeat domains 3, also known as SHANK3, is a human gene on chromosome 22.This gene is a member of the Shank gene family. Shank proteins are multidomain scaffold proteins of the postsynaptic density that connect neurotransmitter receptors, ion channels, and other membrane...

; STARD13

STARD13

StAR-related lipid transfer domain protein 13 also known as deleted in liver cancer 2 protein is a protein that in humans is encoded by the STARD13 gene and a member of the DLC family of proteins.-Function and structure:...

; UBP1

UBP1

Upstream-binding protein 1 is a protein that in humans is encoded by the UBP1 gene.-Further reading:...

;
USH1G

USH1G

Usher syndrome type-1G protein is a protein that in humans is encoded by the USH1G gene.-External Links:* -Further reading:...

; ZCCHC14; p63

TP73L

Tumor protein p63 also known as transformation-related protein 63 is a protein that in humans is encoded by the TP63 gene.TP63 also known as the p63 gene was discovered 20 years after the discovery of the p53 tumor suppressor gene and along with p73 constitutes the p53 gene family based on their...

; p73

P73

p73 is a protein related to the p53 tumor protein. Because of its structural resemblance to p53, it has also been considered a tumor suppressor. It is involved in cell cycle regulation, and induction of apoptosis. Like p53, p73 is characterized by the presence of different isoforms of the protein...

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