SDPR explained

Cavin-2 or Serum deprivation-response protein (SDPR) is a protein that in humans is encoded by the SDPR gene.^{[1] [2] [3]} Cavin-2 is highly expressed in a variety of human endothelial cells.^[4]

This gene has a calcium-independent phospholipid-binding protein whose expression increases in serum-starved cells. This protein has also been shown to be a substrate for protein kinase C (PKC) phosphorylation.^[3]

Function

Cavin-2 is required for blood vessel formation (angiogenesis) in humans and zebrafish and required also for the endothelial cell proliferation, migration and invasion in humans. Cavin-2 plays an important role in endothelial cell maintenance by regulating eNOS activity. Cavin-2 controls the generation of nitric oxide (NO) in human endothelial cells by controlling the activity and stability of the protein endothelial nitric-oxide synthase (eNOS).

Secretion

Cavin-2 is highly secreted from human endothelial cells (HUVEC), they are secreted through endothelial microparticles (EMPs) but not exosomes and is required for EMP biogenesis.

Clinical significance

SDPR is shown to act as a metastasis suppressor by xenograft studies utilizing breast cancer cell lines.^[5] SDPR may elicit its metastasis suppressor function by directly interacting with ERK and limiting its pro-survival role.^[5] Moreover, it is suggested that SDPR is silenced during breast cancer progression by promoter DNA methylation.^[5] Metastasis suppressor role of SDPR may go beyond breast cancer since tumor samples from bladder, colorectal, lung, pancreatic, and ovarian cancers as well as sarcomas also exhibited loss of SDPR expression.^[5]

Further reading

• Burgener R, Wolf M, Ganz T, Baggiolini M . Purification and characterization of a major phosphatidylserine-binding phosphoprotein from human platelets . The Biochemical Journal . 269 . 3 . 729–34 . August 1990 . 2390065 . 1131648 . 10.1042/bj2690729 .
• Cross SH, Charlton JA, Nan X, Bird AP . Purification of CpG islands using a methylated DNA binding column . Nature Genetics . 6 . 3 . 236–44 . March 1994 . 8012384 . 10.1038/ng0394-236 . 12847618 .
• Mineo C, Ying YS, Chapline C, Jaken S, Anderson RG . Targeting of protein kinase Calpha to caveolae . The Journal of Cell Biology . 141 . 3 . 601–10 . May 1998 . 9566962 . 2132740 . 10.1083/jcb.141.3.601 .
• Gevaert K, Goethals M, Martens L, Van Damme J, Staes A, Thomas GR, Vandekerckhove J . Exploring proteomes and analyzing protein processing by mass spectrometric identification of sorted N-terminal peptides . Nature Biotechnology . 21 . 5 . 566–9 . May 2003 . 12665801 . 10.1038/nbt810 . 23783563 .
• Brandenberger R, Wei H, Zhang S, Lei S, Murage J, Fisk GJ, Li Y, Xu C, Fang R, Guegler K, Rao MS, Mandalam R, Lebkowski J, Stanton LW . 6 . Transcriptome characterization elucidates signaling networks that control human ES cell growth and differentiation . Nature Biotechnology . 22 . 6 . 707–16 . June 2004 . 15146197 . 10.1038/nbt971 . 27764390 .
• Rual JF, Venkatesan K, Hao T, Hirozane-Kishikawa T, Dricot A, Li N, Berriz GF, Gibbons FD, Dreze M, Ayivi-Guedehoussou N, Klitgord N, Simon C, Boxem M, Milstein S, Rosenberg J, Goldberg DS, Zhang LV, Wong SL, Franklin G, Li S, Albala JS, Lim J, Fraughton C, Llamosas E, Cevik S, Bex C, Lamesch P, Sikorski RS, Vandenhaute J, Zoghbi HY, Smolyar A, Bosak S, Sequerra R, Doucette-Stamm L, Cusick ME, Hill DE, Roth FP, Vidal M . 6 . Towards a proteome-scale map of the human protein-protein interaction network . Nature . 437 . 7062 . 1173–8 . October 2005 . 16189514 . 10.1038/nature04209 . 2005Natur.437.1173R . 4427026 .

Notes and References

1. Gustincich S, Vatta P, Goruppi S, Wolf M, Saccone S, Della Valle G, Baggiolini M, Schneider C . 6 . The human serum deprivation response gene (SDPR) maps to 2q32-q33 and codes for a phosphatidylserine-binding protein . Genomics . 57 . 1 . 120–9 . April 1999 . 10191091 . 10.1006/geno.1998.5733 .
2. Gustincich S, Schneider C . Serum deprivation response gene is induced by serum starvation but not by contact inhibition . Cell Growth & Differentiation . 4 . 9 . 753–60 . September 1993 . 8241023 .
3. Web site: Entrez Gene: SDPR serum deprivation response (phosphatidylserine binding protein).
4. Boopathy GT, Kulkarni M, Ho SY, Boey A, Chua EW, Barathi VA, Carney TJ, Wang X, Hong W . 6 . Cavin-2 regulates the activity and stability of endothelial nitric-oxide synthase (eNOS) in angiogenesis . The Journal of Biological Chemistry . 292 . 43 . 17760–17776 . October 2017 . 28912276 . 5663877 . 10.1074/jbc.M117.794743 . free .
5. Ozturk S, Papageorgis P, Wong CK, Lambert AW, Abdolmaleky HM, Thiagalingam A, Cohen HT, Thiagalingam S . 6 . SDPR functions as a metastasis suppressor in breast cancer by promoting apoptosis . Proceedings of the National Academy of Sciences of the United States of America . 113 . 3 . 638–43 . January 2016 . 26739564 . 4725521 . 10.1073/pnas.1514663113 . 2016PNAS..113..638O . free .