Tumor Suppressor p16INK4A: Determination of Solution Structure and Analyses of Its Interaction with Cyclin-Dependent Kinase 4

Byeon, In‐Ja L.; Li, Junan; Ericson, Karen L.; Selby, Thomas L.; Tevelev, Anton; Kim, Heejung; O’Maille, Paul E.; Tsai, Ming‐Daw

doi:10.1016/s1097-2765(00)80042-8

Cited by 146 publications

(276 citation statements)

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“…Each AR motif exhibits a canonical helix-turn-helix conformation, in which two R-helices are arranged in an antiparallel fashion and the loop projects outward at an approximately 90°angle to facilitate the formation of hairpinlike -sheets with neighboring loops (12,13). Usually, a hairpinlike -sheet structure consists of the last three residues of the preceding AR and the first four residues of the next AR.…”

Section: Structurementioning

confidence: 99%

“…The loop regions of neighboring ARs are connected in a tail-to-head order to form hairpinlike -sheet structures ( Figure 2). While such hairpinlike structures are relatively flexible in conformation (13), the extended helix bundle is stabilized mainly through inter-and intrarepeat hydrophobic interactions predominantly associated with conserved non- polar residues in the helical regions (Figure 3a), as well as hydrogen bonding interactions between polar residues and the main chain atoms from neighboring repeats (18) (Figure 3b). Since the helices on the far side of the loop generally have larger hydrophobic side chains and are slightly longer than the helices on the near side, the molecule of an AR protein is in a concave shape.…”

Section: Structurementioning

confidence: 99%

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Ankyrin Repeat: A Unique Motif Mediating Protein−Protein Interactions

2006

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Ankyrin repeat, one of the most widely existing protein motifs in nature, consists of 30−34 amino acid residues and exclusively functions to mediate protein−protein interactions, some of which are directly involved in the development of human cancer and other diseases. Each ankyrin repeat exhibits a helix−turn−helix conformation, and strings of such tandem repeats are packed in a nearly linear array to form helix−turn−helix bundles with relatively flexible loops. The global structure of an ankyrin repeat protein is mainly stabilized by intra- and inter-repeat hydrophobic and hydrogen bonding interactions. The repetitive and elongated nature of ankyrin repeat proteins provides the molecular bases of the unique characteristics of ankyrin repeat proteins in protein stability, folding and unfolding, and binding specificity. Recent studies have demonstrated that ankyrin repeat proteins do not recognize specific sequences, and interacting residues are discontinuously dispersed into the whole molecules of both the ankyrin repeat protein and its partner. In addition, the availability of thousands of ankyrin repeat sequences has made it feasible to use rational design to modify the specificity and stability of physiologically important ankyrin repeat proteins and even to generate ankyrin repeat proteins with novel functions through combinatorial chemistry approaches.

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Section: Structurementioning

confidence: 99%

Section: Structurementioning

confidence: 99%

Ankyrin Repeat: A Unique Motif Mediating Protein−Protein Interactions

2006

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“…Using in vitro systems, we have studied the interactions between CDK4 and various proteins (p16, p18, Tax, and gankyrin), in various combinations (16,17,(25)(26)(27). Here, we present biochemical and biophysical studies on p34 SEI-1 / CDK4 interactions under a variety of conditions.…”

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confidence: 99%

The Nuclear Protein p34^SEI^-¹ Regulates the Kinase Activity of Cyclin-Dependent Kinase 4 in a Concentration-Dependent Manner

2004

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Previous studies have shown that p34 SEI-1 , also known as TRIP-Br1, is involved in cell cycle regulations by interacting with a number of important proteins including CDK4. However, the detailed mechanism and structural basis of the interaction remains to be determined. We report the use of in vitro studies to address these problems. First, it was shown that p34 SEI-1 binds to CDK4 directly, and the binding does not compete directly with p16. In the presence of p16, a quaternary complex is formed between p34 SEI-1 , CDK4, cyclin D2, and p16. Second, it was found that p34 SEI-1 activates the kinase activity of CDK4 at lower concentrations (reaching the maximum at 500 nM) but inhibits the same activity at higher concentrations, implying that p34 SEI-1 -mediated CDK4 activation is dose-dependent. Again, the effects of p34 SEI-1 and p16 are independent of each other. Third, it was shown that p34 SEI-1 possesses a LexA-mediated transactivation activity. Finally, a set of truncation mutants were used to dissect the structural elements responsible for the different functions of p34 SEI-1 . The results indicate that the fragment 30-160 can bind, activate, and inhibit CDK4; the fragment 30-132 can bind and activate but does not inhibit CDK4, while the fragment 30-88 cannot bind, activate, or inhibit but retains the LexA-mediated transactivation activity.Mammalian cyclin-dependent kinases (hereafter, CDKs) 1 are a group of conserved serine/threonine protein kinases driving the cell through most of the major cell cycle control points (1-3). In conjunction with different cyclins, CDKs phosphorylate specific substrates, which subsequently turn on/off downstream genes required for cell progression (4). For instance CDK4 and 6, in partnership with D cyclins, specifically phosphorylate the retinobalstoma susceptible gene product (Rb), thus regulating entry into the cell cycle and passage through the checkpoint in late G1 (2). As the central molecules of the machinery controlling cell progression, all CDKs are strictly controlled by multiple mechanisms, such as gene amplification and transcription, holoenzyme assembly, posttranslational modification, and protein/ protein interactions (5). Many proteins have been found to act as negative or positive kinase regulators of CDK4 and 6 through protein/protein interactions. While binding of D cyclins is required for the full kinase activity (4), INK4 (including p16, p15, p18, and p19) (6-11) and KIP (including p21, p27, and p57) proteins (5,(12)(13)(14) are inhibitors of CDK4 and 6. Moreover, the oncoprotein Tax from human T-cell leukemia virus 1 (HTLV-1) stimulates the CDK4 activity in infected cells through physical association (15,16), and the oncoprotein gankyrin affects CDK4 by counteracting against the inhibition of p16 and p18 (17). The intricate regulation of CDK4 and 6 activitied by these and possibly many other proteins is crucial for cell cycling and tumorigenesis.p34 SEI-1 , a nuclear protein originally cloned through a yeast two-hybrid approach using human p16 a...

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“…Mutations at various sites within the CDK4 coding sequence have been found to decrease the a nity to CDK4 for p16 in in vitro binding assays. Among these are variations at amino acids 22, 25, 34 ± 35, 56, 95 ± 101, 181/184 and 281 ± 283 (Coleman et al, 1997;Luh et al, 1997;Byeon et al, 1998;Ceha et al, 1998). These data suggest that at least some p16 binding sites reside outside of the established p16-binding pocket (amino acids 22 ± 25) or that mutations in these other regions result in conformation changes in CDK4, thereby prohibiting CDKN2A from accessing the binding pocket.…”

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Lack of germline CDK6 mutations in familial melanoma

et al. 2000

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Germline mutations in genes encoding several components of the retinoblastoma pathway have been linked with inherited predisposition to melanoma. Most commonly, such mutations involve CDKN2A, a cyclindependant kinase inhibitor of two kinases, CDK4 and CDK6, which phosphorylate the retinoblastoma protein (pRB) and thereby promote passage through the G 1 /S cell-cycle restriction point. Less frequently, germline mutations in the CDK4 gene have also been linked with an increased risk of melanoma. Despite the sequence and functional homology between CDK4 and CDK6, the role of germline mutations in CDK6 in melanoma predisposition is unknown. We detected no CDK6 mutations within the p16 (CDKN2A) binding domain in index cases from 60 melanoma-prone kindreds that lacked germline mutations in the coding regions of either CDKN2A or within the entire CDK4 coding region. We conclude that germline mutations in CDK6 do not make a signi®cant contribution to melanoma predisposition. Oncogene (2000) 19, 1849 ± 1852. Keywords: familial melanoma; CDK6Between 8 and 12% of melanoma cases arise in families with a genetic predisposition to the disease (Tucker and Goldstein, 1995). In a subset of these kindreds, germline coding mutations of the CDKN2A gene (on human chromosome 9p21) co-segregate with cases of melanoma (Hussussian et al., 1994;Walker et al., 1995;Dracopoli and Fountain, 1996;FitzGerald et al., 1996; NL and DH, unpublished). The CDKN2A gene product ± designated p16 ± is a cyclin-dependent kinase (CDK) inhibitor (CDKI). p16 plays a key regulatory role in the retinoblastoma (Rb) pathway at the G 1 /S cell-cycle restriction point by inhibiting the phosphorylation of Rb via CDK4/6 (Kato et al., 1993;Weinberg, 1995;Ruas and Peters, 1998). The genetic basis for melanoma in families and individuals that lack coding mutations of CDKN2A is not well understood at this time. Possible explanations include non-coding mutations of CDKN2A; alterations in other genes located at 9p21; and mutations of other major or minor melanoma predisposition genes located elsewhere in the human genome.Genetic alterations of two other members of the Rb pathway in addition to CDKN2A have been linked with an increased risk of melanoma. Individuals harbouring germline mutations in the Rb gene and who have retinoblastoma as children show an increased risk of melanoma as adults (Draper et al., 1986;Traboulsi et al., 1988;Eng et al., 1993;Bataille et al., 1995). In addition, three melanoma prone families have been reported to possess germline mutations in the CDK4 gene that cosegregate with the disease. Two of these families possess a cysteine rather than the wild-type arginine at amino acid 24 (R24C; Zuo et al., 1996). More recently, an additional mutation at position 24 (R24H) was identi®ed in a single French kindred (Sou®r et al., 1998). Moreover, the R24C (and presumably the R24H) mutant protein has a reduced a nity for p16, resulting in relaxation of control at the G1/S restriction point. CDK6 shows considerable amino acid homology with CDK4 ( Figure...

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Tumor Suppressor p16INK4A: Determination of Solution Structure and Analyses of Its Interaction with Cyclin-Dependent Kinase 4

Cited by 146 publications

References 45 publications

Ankyrin Repeat: A Unique Motif Mediating Protein−Protein Interactions

Ankyrin Repeat: A Unique Motif Mediating Protein−Protein Interactions

The Nuclear Protein p34^SEI^-¹ Regulates the Kinase Activity of Cyclin-Dependent Kinase 4 in a Concentration-Dependent Manner

Lack of germline CDK6 mutations in familial melanoma

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Tumor Suppressor p16INK4A: Determination of Solution Structure and Analyses of Its Interaction with Cyclin-Dependent Kinase 4

Cited by 146 publications

References 45 publications

Ankyrin Repeat: A Unique Motif Mediating Protein−Protein Interactions

Ankyrin Repeat: A Unique Motif Mediating Protein−Protein Interactions

The Nuclear Protein p34SEI-1 Regulates the Kinase Activity of Cyclin-Dependent Kinase 4 in a Concentration-Dependent Manner

Lack of germline CDK6 mutations in familial melanoma

Contact Info

Product

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The Nuclear Protein p34^SEI^-¹ Regulates the Kinase Activity of Cyclin-Dependent Kinase 4 in a Concentration-Dependent Manner