Dickkopf
Dickkopf (DKK) is a family of proteins consisting of five members as of 2020. The most well-studied is Dickkopf-related protein 1 (DKK1).[1] DKK proteins inhibit the Wnt signaling pathway coreceptors LRP5 and LRP6. They bind with high affinity as ligands to KREMEN1 and KREMEN2, which are transmembrane proteins.[2] DKK proteins have important roles in the development of vertebrates.[2]
Dickkopf-related protein 1 | |||||||
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Identifiers | |||||||
Symbol | DKK1 | ||||||
NCBI gene | 22943 | ||||||
HGNC | 2891 | ||||||
OMIM | 605189 | ||||||
RefSeq | NP_036374 | ||||||
UniProt | O94907 | ||||||
Other data | |||||||
Locus | Chr. 10 q21.1 | ||||||
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Dickkopf-related protein 2 | |||||||
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Identifiers | |||||||
Symbol | DKK2 | ||||||
NCBI gene | 27123 | ||||||
HGNC | 2892 | ||||||
OMIM | 605415 | ||||||
RefSeq | NP_055236 | ||||||
UniProt | Q9UBU2 | ||||||
Other data | |||||||
Locus | Chr. 4 q25 | ||||||
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Dickkopf-related protein 3 | |||||||
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Identifiers | |||||||
Symbol | DKK3 | ||||||
NCBI gene | 27122 | ||||||
HGNC | 2893 | ||||||
OMIM | 605416 | ||||||
RefSeq | NP_037385 | ||||||
UniProt | Q9QUN9 | ||||||
Other data | |||||||
Locus | Chr. 11 p15.3 | ||||||
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Dickkopf-related protein 4 | |||||||
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Identifiers | |||||||
Symbol | DKK4 | ||||||
NCBI gene | 27121 | ||||||
HGNC | 2894 | ||||||
OMIM | 605417 | ||||||
RefSeq | NP_055235 | ||||||
UniProt | Q9UBT3 | ||||||
Other data | |||||||
Locus | Chr. 8 p11.21 | ||||||
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Structure
DKK proteins are glycoproteins consisting of 255–350 amino acids. DKK1, DKK2, and DKK4 have similar molecular weights, at 24–29 kDa (kilodaltons). DKK3 is heaviest, at 38 kDa.[2] In addition to having similar weights, DKK1, -2, and -4 have high structural similarity, with two shared cysteine-rich domains. DKK3 differs from -1, -2, and -4 by the presence of a Soggy domain at its N-terminus.[3]
Proteins
Four DKK proteins and one DKK-like protein occur in humans and other vertebrates,[4] with five proteins in the family in total:[5]
Human disease
DKK proteins are believed to be involved with several human diseases, including bone cancer and neurodegenerative disease. Evidence also indicates DKK1 and DKK3 are involved in the pathophysiology of the artery, where they could contribute to atherosclerosis.[3]
References
- Jackstadt R, Hodder MC, Sansom OJ (2020-03-09). "WNT and β-Catenin in Cancer: Genes and Therapy". Annual Review of Cancer Biology. 4 (1): 177–196. doi:10.1146/annurev-cancerbio-030419-033628. ISSN 2472-3428.
- Niehrs C (December 2006). "Function and biological roles of the Dickkopf family of Wnt modulators". Oncogene. 25 (57): 7469–81. doi:10.1038/sj.onc.1210054. PMID 17143291.
- Baetta R, Banfi C (July 2019). "Dkk (Dickkopf) Proteins". Arteriosclerosis, Thrombosis, and Vascular Biology. 39 (7): 1330–1342. doi:10.1161/ATVBAHA.119.312612. PMID 31092014.
- Patel S, Barkell AM, Gupta D, Strong SL, Bruton S, Muskett FW, et al. (August 2018). "Structural and functional analysis of Dickkopf 4 (Dkk4): New insights into Dkk evolution and regulation of Wnt signaling by Dkk and Kremen proteins". The Journal of Biological Chemistry. 293 (31): 12149–12166. doi:10.1074/jbc.RA118.002918. PMC 6078440. PMID 29925589.
- Shao YC, Wei Y, Liu JF, Xu XY (2017). "The role of Dickkopf family in cancers: from Bench to Bedside". American Journal of Cancer Research. 7 (9): 1754–1768. PMC 5622213. PMID 28979801.