Cyclin box fold superfamily; The cyclin box is a protein binding domain that functions in cell-cycle and transcriptional control. It is about 100 amino acids in length, composed of five helices, and is present in cyclins, transcription initiation factor IIB (TFIIB), and retinoblastoma tumour suppressor protein (Rb). Cyclins consist of 8 classes of cell cycle regulators that function as regulatory subunits of cyclin-dependent kinases (CDKs), which are serine/threonine kinases. The catalytic activities of CDKs are modulated not only by their interactions with cyclins but also by CDK inhibitors (CKIs). CDKs, cyclins and CKIs play key roles in transcription, epigenetic regulation, metabolism, stem cell self-renewal, neuronal functions, and spermatogenesis. TFIIB is a transcription factor that binds the TATA box. Members in this superfamily contain one or two copies of the cyclin box.

                        10        20        30
                ....*....|....*....|....*....|....*..
gi 38482680  84 PTPYCFMRRFLKAAQSEKKLELLSFFMIELSLVEYEM 120
Cdd:cd20511   1 PTPYVFLVRFLKAAQSDKKLENLAFFLVELGLVEYEM 37

Cyclin, N-terminal domain; Cyclins regulate cyclin dependent kinases (CDKs). Swiss:P22674 is a Uracil-DNA glycosylase that is related to other cyclins. Cyclins contain two domains of similar all-alpha fold, of which this family corresponds with the N-terminal domain.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 38482680     1 ELLEETLFLTVNIIDRFLARENVVRKKLQLAGVTAMLLACKYEEVSVPVVEDLILICDRAYTRADILEMERRIVNTLNFN 80
Cdd:pfam00134  46 KLLPETLYLAVNYLDRFLSKKSVPKNKLQLVGVTCLFIAAKYEEIYPPTVEDLVYITDNAYTREEILRMERLILETLNFD 125

                  ..
gi 38482680    81 MS 82
Cdd:pfam00134 126 LS 127

second cyclin box found in Arabidopsis thaliana B-type cyclins (CycBs) and similar proteins; Plant B-type cyclins (CycBs) correspond to a group of G2/mitotic-specific cyclins that are functionally linked to S- and M-phases of the mitotic cycle, which predicts their involvement also in meiosis. CycBs associate with their partner cyclin-dependent kinases (CDKs) to trigger the kinase activity. They contain two cyclin boxes. This model corresponds to the second one. The cyclin box is a protein binding domain.

                        10        20        30
                ....*....|....*....|....*....|....*..
gi 38482680  84 PTPYCFMRRFLKAAQSEKKLELLSFFMIELSLVEYEM 120
Cdd:cd20511   1 PTPYVFLVRFLKAAQSDKKLENLAFFLVELGLVEYEM 37

Cyclin, C-terminal domain; Cyclins regulate cyclin dependent kinases (CDKs). Swiss:P22674 is a Uracil-DNA glycosylase that is related to other cyclins. Cyclins contain two domains of similar all-alpha fold, of which this family corresponds with the C-terminal domain.

                          10        20        30
                  ....*....|....*....|....*....|....*....
gi 38482680    84 PTPYCFMRRFLKAAQS--EKKLELLSFFMIELSLVEYEM 120
Cdd:pfam02984   1 PTPLSFLRRFSKAADYlhDLELRTLAKYLLELTLLDYDF 39

first cyclin box found in Arabidopsis thaliana B-type cyclins (CycBs) and similar proteins; Plant B-type cyclins (CycBs) correspond to a group of G2/mitotic-specific cyclins that are functionally linked to S- and M-phases of the mitotic cycle, which predicts their involvement also in meiosis. CycBs associate with their partner cyclin-dependent kinases (CDKs) to trigger the kinase activity. They contain two cyclin boxes. This model corresponds to the first one. The cyclin box is a protein binding domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 38482680   1 ELLEETLFLTVNIIDRFLARENVVRKKLQLAGVTAMLLACKYEEVSVPVVEDLILICDRAYTRADILEMERRIVNTLNF 79
Cdd:cd20567  69 ELMPETLYLTVNLIDRFLSVKQVPRKELQLVGVTAMLIASKYEEIWAPEVNDFVYISDNAYTRKQILVMEKTMLNTLEF 147

Cyclin [Cell division and chromosome partitioning];

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 38482680   2 LLEETLFLTVNIIDRFLARENVVRKKLQLAGVTAMLLACKYEEVSVPVVEDLILICDRAYTRADILEMERRIVNTLNFNM 81
Cdd:COG5024 229 LLPETLFLAINIIDRFLSSRVVSLEKYQLVGISALFIASKYEEVNCPSIKDLVYATDGAFTRDDIIRAERYMLEVLDFNI 308

                        90       100       110
                ....*....|....*....|....*....|....*...
gi 38482680  82 SVPTPYCFMRRFLKAAQSEKKLELLSFFMIELSLVEYE 119
Cdd:COG5024 309 SWPSPMSFLRRISKASDYDIFSRTPAKFSSEISPVDYK 346

first cyclin box found in cyclin-A (CCNA) family; The CCNA family includes two A-type cyclins, CCNA1 and CCNA2. CCNA1 may primarily function in the control of the germline meiotic cell cycle and additionally in the control of mitotic cell cycle in some somatic cells. CCNA2 controls both the G1/S and the G2/M transition phases of the cell cycle. Members in this family contain two cyclin boxes. The model corresponds to the first one. The cyclin box is a protein binding domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 38482680   2 LLEETLFLTVNIIDRFLARENVVRKKLQLAGVTAMLLACKYEEVSVPVVEDLILICDRAYTRADILEMERRIVNTLNF 79
Cdd:cd20504  51 LVPETLYLAVNYIDRFLSQMSVLRSKLQLVGTACMFIAAKYEEIYPPEVEEFVYITDDTYTKKQVLRMEHLVLKVLSF 128

first cyclin box found in Arabidopsis thaliana A-type cyclins (CycAs) and similar proteins; Plant A-type cyclins (CycAs) correspond to a group of G2/mitotic-specific cyclins that are functionally linked to S- and M-phases of the mitotic cycle, which predicts their involvement also in meiosis. CycAs associate with their partner cyclin-dependent kinases (CDKs) to trigger the kinase activity. They contain two cyclin boxes. This model corresponds to the first one. The cyclin box is a protein binding domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 38482680   1 ELLEETLFLTVNIIDRFLARENVVRKKLQLAGVTAMLLACKYEEVSVPVVEDLILICDRAYTRADILEMERRIVNTLNF 79
Cdd:cd20562  57 KLVPDTLYLTVSYIDRFLSGNYVNRQRLQLLGVSCMLIASKYEEICAPQVEEFCYITDNTYTKQEVLEMEIDVLNALQF 135

first cyclin box found in G2/mitotic-specific cyclin-B1 (CCNB1); CCNB1 is essential for the control of the cell cycle at the G2/M (mitosis) transition. It is required for embryo development. Over-expression of human CCNB1 has been found in numerous cancers and has been associated with tumor aggressiveness. CCNB1 contains two cyclin boxes. This model corresponds to the first one. The cyclin box is a protein binding domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 38482680   2 LLEETLFLTVNIIDRFLARENVVRKKLQLAGVTAMLLACKYEEVSVPVVEDLILICDRAYTRADILEMERRIVNTLNF 79
Cdd:cd20565  52 LLQETMYMTVAIIDRFLQNNPVPKKMLQLVGVTAMFIASKYEEMYPPEIGDFAFVTDNTYTKHQIRQMEMKILRALDF 129

first cyclin box found in cyclin-A2 (CCNA2) and similar proteins; CCNA2 controls both the G1/S and the G2/M transition phases of the cell cycle. It is significantly over-expressed in various cancer types, and can be used as a prognostic biomarker for estrogen receptor positive (ER+) breast cancer and tamoxifen resistance. CCNA2 contains two cyclin boxes. This model corresponds to the first one. The cyclin box is a protein binding domain.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 38482680   1 ELLEETLFLTVNIIDRFLARENVVRKKLQLAGVTAMLLACKYEEVSVPVVEDLILICDRAYTRADILEMERRIVNTLNFN 80
Cdd:cd20561  52 KLQNETLHLAVNYIDRFLSSMSVLRGKLQLVGTAAMLLASKFEEIYPPEVAEFVYITDDTYTKKQVLRMEHLVLKVLTFD 131

first cyclin box found in cyclin-A1 (CCNA1); CCNA1 may primarily function in the control of the germline meiotic cell cycle and additionally in the control of mitotic cell cycle in some somatic cells. CCNA1 contains two cyclin boxes. This model corresponds to the first one. The cyclin box is a protein binding domain.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 38482680   1 ELLEETLFLTVNIIDRFLARENVVRKKLQLAGVTAMLLACKYEEVSVPVVEDLILICDRAYTRADILEMERRIVNTLNFN 80
Cdd:cd20560  84 KLQTETLYLAVNYLDRFLSCMSVLRGKLQLVGTAAILLASKYEEIYPPEVDEFVYITDDTYTKKQLLRMEHLLLKVLAFD 163

first cyclin box found in G1/S-specific cyclin-E (CCNE) family; The CCNE family includes two E-type cyclins, CCNE1 and CCNE2. CCNE1 is essential for the control of the cell cycle at the G1/S (start) transition. It interacts with CDK2 protein kinase to form a serine/threonine kinase holoenzyme complex. CCNE2 is essential for the control of the cell cycle at the late G1 and early S phase. It interacts with the CDK2 (in vivo) and CDK3 (in vitro) protein kinases to form a serine/threonine kinase holoenzyme complexes. Members of this family contain two cyclin boxes. This model corresponds to the first one. The cyclin box is a protein binding domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 38482680   5 ETLFLTVNIIDRFLARENVVRK-KLQLAGVTAMLLACKYEEVSVPVVEDLILICDRAYTRADILEMERRIVNTLNF 79
Cdd:cd20519  56 ETFYLAVDFVDRYLSTQTNVPKtQLQLIGITCLFIAAKLEEIYPPKLSEFAYVTDGACTEDEILTMELIILKALNW 131

domain present in cyclins, TFIIB and Retinoblastoma; A helical domain present in cyclins and TFIIB (twice) and Retinoblastoma (once). A protein recognition domain functioning in cell-cycle and transcription control.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 38482680      1 ELLEETLFLTVNIIDRFLARENVVRKKLQLAGVTAMLLACKYEEVSVPVVEDLILICDraYTRADILEMERRIVN 75
Cdd:smart00385  11 NLDPETLNLAVNLLDRFLSDYKFLKYSPSLIAAAALYLASKTEETPPWTKELVHYTGY--FTEEEILRMERLLLE 83

first cyclin box found in G2/mitotic-specific cyclin-F (CCNF) and similar proteins; CCNF, also termed F-box only protein 1 (FBXO1), is a substrate recognition component of a SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of CP110 during G2 phase, thereby acting as an inhibitor of centrosome reduplication. It is the largest among all cyclins and oscillates in the cell cycle like other cyclins. CCNF contains two cyclin boxes. This model corresponds to the first one. The cyclin box is a protein binding domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 38482680   5 ETLFLTVNIIDRFLARENVVRKKLQLAGVTAMLLACKYEEVSVPVVEDLILICDRAYTRADILEMERRIVNTL 77
Cdd:cd20521  23 LTLHVAVSCVDRYLMVRKVPRSKLQLLGIACMVIATRFLGKDILTIREAAWLTDNTYKYEDVVRMMGEIVAAL 95

first cyclin box found in G1/S-specific cyclin-E2 (CCNE2); CCNE2 is essential for the control of the cell cycle at the late G1 and early S phase. It interacts with the CDK2 (in vivo) and CDK3 (in vitro) protein kinases to form a serine/threonine kinase holoenzyme complexes. CCNE2 contains two cyclin boxes. This model corresponds to the first one. The cyclin box is a protein binding domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 38482680   2 LLEETLFLTVNIIDRF-LARENVVRKKLQLAGVTAMLLACKYEEVSVPVVEDLILICDRAYTRADILEMERRIVNTLNF 79
Cdd:cd20580  59 LHRETFYLAQDFFDRFmLTQKNINKSMLQLIGITSLFIASKLEEIYPPKLHEFAYVTDGACSEDDILDMELIILKALKW 137

first cyclin box found in cyclin-D (CCND) family; The CCND family includes three mitogen-induced D-type cyclins, CCND1, CCND2 and CCND3, which function as regulatory subunits of the cyclin-dependent kinases CDK4 and CDK6, that drive progression through the G1 phase of the cell cycle. Members in this family contain two cyclin boxes. This model corresponds to the first one. The cyclin box is a protein binding domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 38482680   4 EETLFLTVNIIDRFLARENVVRKKLQLAGVTAMLLACKYEEVSVPVVEDLILICDRAYTRADILEMERRIVNTL 77
Cdd:cd20515  74 EEVFPLAVNYLDRFLSLVPIRKSQLQLLGAVCLFLASKLKETIPLTAEKLCIYTDNSITLQELLDWELLVLTKL 147

second cyclin box found in cyclin-O (CCNO) and similar proteins; This subfamily is composed of CCNO and similar proteins including Schizosaccharomyces pombe meiosis-specific cyclin rem1, Drosophila melanogaster G2/mitotic-specific cyclin-A (CCNA), and Candida albicans G1/S-specific cyclin CCN1, among others. Rem1 is required for pre-meiotic DNA synthesis and S phase progression. CCNA is essential for the control of the cell cycle at the G2/M (mitosis) transition. CCN1 is essential for the control of the cell cycle at the G1/S (start) transition and for maintenance of filamentous growth. CCNO is specifically required for generation of multiciliated cells, possibly by promoting a cell cycle state compatible with centriole amplification and maturation. It is involved in the activation of cyclin-dependent kinase 2. Members of this subfamily contain two cyclin boxes. This model corresponds to the second one. The cyclin box is a protein binding domain.

                        10        20        30
                ....*....|....*....|....*....|....*..
gi 38482680  84 PTPYCFMRRFLKAAQSEKKLELLSFFMIELSLVEYEM 120
Cdd:cd20537   1 PTPLSFLRRYLSLLGLDEKVRHLARYLLELSLLDYEF 37

cyclin box found in the cyclin-G (CCNG) family; The CCNG family includes two cyclins, CCNG1 and CCNG2. CCNG1 is the only cyclin that has either positive or negative effects on cell growth. It is associated with G2/M phase arrest in response to DNA damage. It is also involved in the development of human carcinoma. CCNG2 may play a role in growth regulation and in negative regulation of cell cycle progression. It has been identified as a tumor suppressor in several cancers. Members of this family contain one cyclin box. The cyclin box is a protein binding domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 38482680   5 ETLFLTVNIIDRFLARENVVRKKLQLAGVTAMLLACKY--EEVSVPVVEDLILICDRAYTRADILEMERRIVNTL 77
Cdd:cd20523  20 ETFALAVNLLDRFLSKVKVKPKHLACITVSCFHIAIKSveEDQNIPSAEDLIRISQCGCTAADLMRMEGIILEKL 94

cyclin box found in cyclin-G1 (CCNG1) and similar proteins; CCNG1 is the only cyclin that has either positive or negative effects on cell growth. It is associated with G2/M phase arrest in response to DNA damage. It is also involved in the development of human carcinoma. CCNG1 contains one cyclin box. The cyclin box is a protein binding domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 38482680   5 ETLFLTVNIIDRFLARENVVRKKLQLAGVTAMLLACKY--EEVSVPVVEDLILICDRAYTRADILEMERRIVNTLNF 79
Cdd:cd20583  21 ETFSLAVNLLDRFLAKMKVQPKHLGCVGLSCFYLAVKAieEERNVPLATDLIRISQYRFTVSDMMRMEKIILEKLCW 97

Cyclin box fold superfamily; The cyclin box is a protein binding domain that functions in cell-cycle and transcriptional control. It is about 100 amino acids in length, composed of five helices, and is present in cyclins, transcription initiation factor IIB (TFIIB), and retinoblastoma tumour suppressor protein (Rb). Cyclins consist of 8 classes of cell cycle regulators that function as regulatory subunits of cyclin-dependent kinases (CDKs), which are serine/threonine kinases. The catalytic activities of CDKs are modulated not only by their interactions with cyclins but also by CDK inhibitors (CKIs). CDKs, cyclins and CKIs play key roles in transcription, epigenetic regulation, metabolism, stem cell self-renewal, neuronal functions, and spermatogenesis. TFIIB is a transcription factor that binds the TATA box. Members in this superfamily contain one or two copies of the cyclin box.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 38482680   1 ELLEETLFLTVNIIDRFLARENVVRKKLQLAGVTAMLLACKYEEVSVPvVEDLILICDraYTRADILEMERR 72
Cdd:cd00043  14 GLPEEVLELAIELLDRFLSKGLLLGRSPELIAAACLYLACKLEELPRT-LKEIAKVSG--VSEKELRKAEKE 82

second cyclin box found in cyclin-B1 (CCNB1)-like family; The CCNB1-like family includes two B-type cyclins, CCNB1 and CCNB2, both of which are essential for the control of the cell cycle at the G2/M (mitosis) transition. Members in this family contain two cyclin boxes. This model corresponds to the second one. The cyclin box is a protein binding domain.

                        10        20        30
                ....*....|....*....|....*....|....*..
gi 38482680  84 PTPYCFMRRFLKAAQSEKKLELLSFFMIELSLVEYEM 120
Cdd:cd20509   1 PLPLHFLRRFSKAGGADAQKHTLAKYLMELTLLDYDM 37

first cyclin box found in G1/S-specific cyclin-D2 (CCND2); CCND2 is a regulatory component of the cyclin D2-CDK4 (DC) complex that phosphorylates and inhibits members of the retinoblastoma (RB) protein family, including RB1, and regulates the cell-cycle during G(1)/S transition. It is a critical mediator of exercise-induced cardiac hypertrophy. It also acts as a regulator of cell cycle proteins affecting SAMHD1-mediated HIV-1 restriction in non-proliferating macrophages. CCND2 contains two cyclin boxes. This model corresponds to the first one. The cyclin box is a protein binding domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 38482680   4 EETLFLTVNIIDRFLARENVVRKKLQLAGVTAMLLACKYEEVSVPVVEDLILICDRAYTRADILEMERRIVNTLNFN 80
Cdd:cd20574  74 EEVFPLAMNYLDRFLAVVPTRKCHLQLLGAVCMFLASKLKETIPLTAEKLCIYTDNSIKPQELLEWELVVLGKLKWN 150

first cyclin box found in viral cyclin (v-cyclin); v-Cyclin modulates host cell cycle progression and apoptotic signaling pathways. It forms an active kinase complex with cellular CDK6, a cellular cyclin-dependent kinase known to interact with cellular type D cyclins. v-Cyclin belongs to Cyclin D subfamily. It contains two cyclin boxes. This model corresponds to the first one. The cyclin box is a protein binding domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 38482680   3 LEETLF-LTVNIIDRFLARENVVRKKLQLAGVTAMLLACKYEEVSVPVVEDLILICDRAYTRADILEMERRIVNTL 77
Cdd:cd20517  22 LDKNVFpLAVSLLDRLLLKKQGTKETLQKTGAACLLIASKIRTVKPITVSKLTYLSCDCFTNLELINQEKDILEAL 97

second cyclin box found in G2/mitotic-specific cyclin-B3 (CCNB3) and similar proteins; CCNB3 is a mitotic B-type cyclin that promotes the metaphase-anaphase transition. It controls anaphase onset independent of spindle assembly checkpoint in meiotic oocytes. CCNB3 contains two cyclin boxes. This model corresponds to the second one. The cyclin box is a protein binding domain.

                        10        20        30
                ....*....|....*....|....*....|....*.
gi 38482680  84 PTPYCFMRRFLKAAQSEKKLELLSFFMIELSLVEYE 119
Cdd:cd20510   1 PLSYRFLRRYAKCARASMETLTLARYILELSLMEYQ 36