:SPR domain
{{Infobox protein family
| Symbol = SPR
| Name = Sprouty
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| Pfam = PF05210
| Pfam_clan =
| InterPro = IPR007875
| SMART =
| PROSITE =
| MEROPS =
| SCOP =
| TCDB =
| OPM family =
| OPM protein =
| CAZy =
| CDD =
}}
In molecular biology the SPR domain is a protein domain found in the Sprouty (Spry) and Spred (Sprouty related EVH1 domain) proteins. These have been identified as inhibitors of the Ras/mitogen-activated protein kinase (MAPK) cascade, a pathway crucial for developmental processes initiated by activation of various receptor tyrosine kinases.{{cite journal | vauthors = Zhang S, Lin Y, Itäranta P, Yagi A, Vainio S | title = Expression of Sprouty genes 1, 2 and 4 during mouse organogenesis | journal = Mechanisms of Development | volume = 109 | issue = 2 | pages = 367–70 | date = December 2001 | pmid = 11731251 | doi = 10.1016/S0925-4773(01)00526-3 | s2cid = 17189370 | doi-access = }} These proteins share a conserved, C-terminal cysteine-rich region, the SPR domain. This domain has been defined as a novel cytosol to membrane translocation domain.{{cite journal | vauthors = Lim J, Yusoff P, Wong ES, Chandramouli S, Lao DH, Fong CW, Guy GR | title = The cysteine-rich sprouty translocation domain targets mitogen-activated protein kinase inhibitory proteins to phosphatidylinositol 4,5-bisphosphate in plasma membranes | journal = Molecular and Cellular Biology | volume = 22 | issue = 22 | pages = 7953–66 | date = November 2002 | pmid = 12391162 | pmc = 134720 | doi = 10.1128/MCB.22.22.7953-7966.2002 }}{{cite journal | vauthors = King JA, Straffon AF, D'Abaco GM, Poon CL, I ST, Smith CM, Buchert M, Corcoran NM, Hall NE, Callus BA, Sarcevic B, Martin D, Lock P, Hovens CM | title = Distinct requirements for the Sprouty domain for functional activity of Spred proteins | journal = The Biochemical Journal | volume = 388 | issue = Pt 2 | pages = 445–54 | date = June 2005 | pmid = 15683364 | pmc = 1138951 | doi = 10.1042/BJ20041284 }}{{cite journal | vauthors = Lim J, Wong ES, Ong SH, Yusoff P, Low BC, Guy GR | title = Sprouty proteins are targeted to membrane ruffles upon growth factor receptor tyrosine kinase activation. Identification of a novel translocation domain | journal = The Journal of Biological Chemistry | volume = 275 | issue = 42 | pages = 32837–45 | date = October 2000 | pmid = 10887178 | doi = 10.1074/jbc.M002156200 | doi-access = free }}{{cite journal | vauthors = Wakioka T, Sasaki A, Kato R, Shouda T, Matsumoto A, Miyoshi K, Tsuneoka M, Komiya S, Baron R, Yoshimura A | title = Spred is a Sprouty-related suppressor of Ras signalling | journal = Nature | volume = 412 | issue = 6847 | pages = 647–51 | date = August 2001 | pmid = 11493923 | doi = 10.1038/35088082 | bibcode = 2001Natur.412..647W | s2cid = 4345140 }} It has been found to be a PtdIns(4,5)P2-binding domain that targets the proteins to a cellular localization that maximizes their inhibitory potential.{{cite journal | vauthors = Hanafusa H, Torii S, Yasunaga T, Nishida E | title = Sprouty1 and Sprouty2 provide a control mechanism for the Ras/MAPK signalling pathway | journal = Nature Cell Biology | volume = 4 | issue = 11 | pages = 850–8 | date = November 2002 | pmid = 12402043 | doi = 10.1038/ncb867 | s2cid = 31064800 }} It also mediates homodimer formation of these proteins.
The SPR domain can occur in association with the WH1 domain (see {{InterPro|IPR000697}}) (located in the N-terminus) in the Spred proteins.