Src homology 2 (SH2) domain; In general, SH2 domains are involved in signal transduction; they bind pTyr-containing polypeptide ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites. They are present in a wide array of proteins including: adaptor proteins (Nck1, Crk, Grb2), scaffolds (Slp76, Shc, Dapp1), kinases (Src, Syk, Fps, Tec), phosphatases (Shp-1, Shp-2), transcription factors (STAT1), Ras signaling molecules (Ras-Gap), ubiquitination factors (c-Cbl), cytoskeleton regulators (Tensin), signal regulators (SAP), and phospholipid second messengers (PLCgamma), amongst others.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034613213 226 DGAYTVRPSSGPHGSQPFTLAVLLRGRVFNIPIRRLDGGRHYALGREGRnREELFSSVAAMVQHFMWHPLPLVDRHSGSR 305
Cdd:cd09929    33 DGTFLVRDSSGKDSSQPYTLMVLYNDKVYNIQIRFLENTRQYALGTGLR-GEETFSSVAEIIEHHQKTPLLLIDGKDNTK 111

                          90
                  ....*....|
gi 1034613213 306 ELTCLLFPTK 315
Cdd:cd09929   112 DSTCLLYAAG 121

Src homology 2 (SH2) domain found in B-cell linker (BLNK) protein and SH2 domain-containing leukocyte protein of 76 kDa (SLP-76); BLNK (also known as SLP-65 or BASH) is an important adaptor protein expressed in B-lineage cells. BLNK consists of a N-terminal sterile alpha motif (SAM) domain and a C-terminal SH2 domain. BLNK is a cytoplasmic protein, but a part of it is bound to the plasma membrane through an N-terminal leucine zipper motif and transiently bound to a cytoplasmic domain of Iga through its C-terminal SH2 domain upon B cell antigen receptor (BCR)-stimulation. A non-ITAM phosphotyrosine in Iga is necessary for the binding with the BLNK SH2 domain and/or for normal BLNK function in signaling and B cell activation. Upon phosphorylation BLNK binds Btk and PLCgamma2 through their SH2 domains and mediates PLCgamma2 activation by Btk. BLNK also binds other signaling molecules such as Vav, Grb2, Syk, and HPK1. BLNK has been shown to be necessary for BCR-mediated Ca2+ mobilization, for the activation of mitogen-activated protein kinases such as ERK, JNK, and p38 in a chicken B cell line DT40, and for activation of transcription factors such as NF-AT and NF-kappaB in human or mouse B cells. BLNK is involved in B cell development, B cell survival, activation, proliferation, and T-independent immune responses. BLNK is structurally homologous to SLP-76. SLP-76 and (linker for activation of T cells) LAT are adaptor/linker proteins in T cell antigen receptor activation and T cell development. BLNK interacts with many downstream signaling proteins that interact directly with both SLP-76 and LAT. New data suggest functional complementation of SLP-76 and LAT in T cell antigen receptor function with BLNK in BCR function. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034613213 226 DGAYTVRPSSGPHGSQPFTLAVLLRGRVFNIPIRRLDGGRHYALGREGRnREELFSSVAAMVQHFMWHPLPLVDRHSGSR 305
Cdd:cd09929    33 DGTFLVRDSSGKDSSQPYTLMVLYNDKVYNIQIRFLENTRQYALGTGLR-GEETFSSVAEIIEHHQKTPLLLIDGKDNTK 111

                          90
                  ....*....|
gi 1034613213 306 ELTCLLFPTK 315
Cdd:cd09929   112 DSTCLLYAAG 121

N-terminal domain of transcription factor Specificity Protein (SP) 2; Specificity Proteins (SPs) are transcription factors that are involved in many cellular processes, including cell differentiation, cell growth, apoptosis, immune responses, response to DNA damage, and chromatin remodeling. SP2 contains the least conserved DNA-binding domain within the SP subfamily of proteins, and its DNA sequence specificity differs from the other SP proteins. It localizes primarily within subnuclear foci associated with the nuclear matrix, and can activate, or in some cases, repress expression from different promoters. The transcription factor SP2 serves as a paradigm for indirect genomic binding. It does not require its DNA-binding domain for genomic DNA binding and occupies target promoters independently of whether they contain a cognate DNA-binding motif. SP2 belongs to a family of proteins, called the SP/Kruppel or Krueppel-like Factor (KLF) family, characterized by a C-terminal DNA-binding domain of 81 amino acids consisting of three Kruppel-like C2H2 zinc fingers. These factors bind to a loose consensus motif, namely NNRCRCCYY (where N is any nucleotide; R is A/G, and Y is C/T), such as the recurring motifs in GC and GT boxes (5'-GGGGCGGGG-3' and 5-GGTGTGGGG-3') that are present in promoters and more distal regulatory elements of mammalian genes. SP factors preferentially bind GC boxes, while KLFs bind CACCC boxes. Another characteristic hallmark of SP factors is the presence of the Buttonhead (BTD) box CXCPXC, just N-terminal to the zinc fingers. The function of the BTD box is unknown, but it is thought to play an important physiological role. Another feature of most SP factors is the presence of a conserved amino acid stretch, the so-called SP box, located close to the N-terminus. SP factors may be separated into three groups based on their domain architecture and the similarity of their N-terminal transactivation domains: SP1-4, SP5, and SP6-9. The transactivation domains between the three groups are not homologous to one another. SP1-4 have similar N-terminal transactivation domains characterized by glutamine-rich regions, which, in most cases, have adjacent serine/threonine-rich regions. This model represents the N-terminal domain of SP2.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034613213 101 PSKPSPPLPQPTML------KGAVSLPvagkQGPIFGRREQGASSRVVPGPPKKPDEDLYLECEPDPVLALTQTLSFQ-V 173
Cdd:cd22540   278 PGTGQPAVLQQVQVlqpkqeQQVVQIP----QQALRVVQAASATLPTVPQKPLQNIQIQNSEPTPTQVYIKTPSGEVQtV 353

                          90       100       110       120       130
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 1034613213 174 LMPSGPlprTSVVPRPTTAPQETRNGTADAASKGRKS--------SLPSVAPTGS 220
Cdd:cd22540   354 LLQEAP---AATATPSSSTSTVQQQVTANNGTGTSKPnynvrkerTLPKIAPAGG 405

Src homology 2 (SH2) domain found in B-cell linker (BLNK) protein and SH2 domain-containing leukocyte protein of 76 kDa (SLP-76); BLNK (also known as SLP-65 or BASH) is an important adaptor protein expressed in B-lineage cells. BLNK consists of a N-terminal sterile alpha motif (SAM) domain and a C-terminal SH2 domain. BLNK is a cytoplasmic protein, but a part of it is bound to the plasma membrane through an N-terminal leucine zipper motif and transiently bound to a cytoplasmic domain of Iga through its C-terminal SH2 domain upon B cell antigen receptor (BCR)-stimulation. A non-ITAM phosphotyrosine in Iga is necessary for the binding with the BLNK SH2 domain and/or for normal BLNK function in signaling and B cell activation. Upon phosphorylation BLNK binds Btk and PLCgamma2 through their SH2 domains and mediates PLCgamma2 activation by Btk. BLNK also binds other signaling molecules such as Vav, Grb2, Syk, and HPK1. BLNK has been shown to be necessary for BCR-mediated Ca2+ mobilization, for the activation of mitogen-activated protein kinases such as ERK, JNK, and p38 in a chicken B cell line DT40, and for activation of transcription factors such as NF-AT and NF-kappaB in human or mouse B cells. BLNK is involved in B cell development, B cell survival, activation, proliferation, and T-independent immune responses. BLNK is structurally homologous to SLP-76. SLP-76 and (linker for activation of T cells) LAT are adaptor/linker proteins in T cell antigen receptor activation and T cell development. BLNK interacts with many downstream signaling proteins that interact directly with both SLP-76 and LAT. New data suggest functional complementation of SLP-76 and LAT in T cell antigen receptor function with BLNK in BCR function. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034613213 226 DGAYTVRPSSGPHGSQPFTLAVLLRGRVFNIPIRRLDGGRHYALGREGRnREELFSSVAAMVQHFMWHPLPLVDRHSGSR 305
Cdd:cd09929    33 DGTFLVRDSSGKDSSQPYTLMVLYNDKVYNIQIRFLENTRQYALGTGLR-GEETFSSVAEIIEHHQKTPLLLIDGKDNTK 111

                          90
                  ....*....|
gi 1034613213 306 ELTCLLFPTK 315
Cdd:cd09929   112 DSTCLLYAAG 121

Src homology 2 (SH2) domain; In general, SH2 domains are involved in signal transduction; they bind pTyr-containing polypeptide ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites. They are present in a wide array of proteins including: adaptor proteins (Nck1, Crk, Grb2), scaffolds (Slp76, Shc, Dapp1), kinases (Src, Syk, Fps, Tec), phosphatases (Shp-1, Shp-2), transcription factors (STAT1), Ras signaling molecules (Ras-Gap), ubiquitination factors (c-Cbl), cytoskeleton regulators (Tensin), signal regulators (SAP), and phospholipid second messengers (PLCgamma), amongst others.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1034613213 225 EDGAYTVRPSSGPHGSqpFTLAVLLR-GRVFNIPIRRLDGGRHYALGREGRnreelFSSVAAMVQHF 290
Cdd:cd00173    20 PDGTFLVRESSSEPGD--YVLSVRSGdGKVKHYLIERNEGGYYLLGGSGRT-----FPSLPELVEHY 79

N-terminal domain of transcription factor Specificity Protein (SP) 2; Specificity Proteins (SPs) are transcription factors that are involved in many cellular processes, including cell differentiation, cell growth, apoptosis, immune responses, response to DNA damage, and chromatin remodeling. SP2 contains the least conserved DNA-binding domain within the SP subfamily of proteins, and its DNA sequence specificity differs from the other SP proteins. It localizes primarily within subnuclear foci associated with the nuclear matrix, and can activate, or in some cases, repress expression from different promoters. The transcription factor SP2 serves as a paradigm for indirect genomic binding. It does not require its DNA-binding domain for genomic DNA binding and occupies target promoters independently of whether they contain a cognate DNA-binding motif. SP2 belongs to a family of proteins, called the SP/Kruppel or Krueppel-like Factor (KLF) family, characterized by a C-terminal DNA-binding domain of 81 amino acids consisting of three Kruppel-like C2H2 zinc fingers. These factors bind to a loose consensus motif, namely NNRCRCCYY (where N is any nucleotide; R is A/G, and Y is C/T), such as the recurring motifs in GC and GT boxes (5'-GGGGCGGGG-3' and 5-GGTGTGGGG-3') that are present in promoters and more distal regulatory elements of mammalian genes. SP factors preferentially bind GC boxes, while KLFs bind CACCC boxes. Another characteristic hallmark of SP factors is the presence of the Buttonhead (BTD) box CXCPXC, just N-terminal to the zinc fingers. The function of the BTD box is unknown, but it is thought to play an important physiological role. Another feature of most SP factors is the presence of a conserved amino acid stretch, the so-called SP box, located close to the N-terminus. SP factors may be separated into three groups based on their domain architecture and the similarity of their N-terminal transactivation domains: SP1-4, SP5, and SP6-9. The transactivation domains between the three groups are not homologous to one another. SP1-4 have similar N-terminal transactivation domains characterized by glutamine-rich regions, which, in most cases, have adjacent serine/threonine-rich regions. This model represents the N-terminal domain of SP2.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034613213 101 PSKPSPPLPQPTML------KGAVSLPvagkQGPIFGRREQGASSRVVPGPPKKPDEDLYLECEPDPVLALTQTLSFQ-V 173
Cdd:cd22540   278 PGTGQPAVLQQVQVlqpkqeQQVVQIP----QQALRVVQAASATLPTVPQKPLQNIQIQNSEPTPTQVYIKTPSGEVQtV 353

                          90       100       110       120       130
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 1034613213 174 LMPSGPlprTSVVPRPTTAPQETRNGTADAASKGRKS--------SLPSVAPTGS 220
Cdd:cd22540   354 LLQEAP---AATATPSSSTSTVQQQVTANNGTGTSKPnynvrkerTLPKIAPAGG 405