Podocalyxin

Podocalyxin, a sialoglycoprotein, is thought to be the major constituent of the glycocalyx of podocytes.[1] It is a member of the CD34 family of transmembrane sialomucins.[2] It coats the secondary foot processes of the podocytes. It is negatively charged and thus functions to keep adjacent foot processes separated, thereby keeping the urinary filtration barrier open.[3] This function is further supported by knockout studies in mice which reveal an essential role in podocyte morphogenesis.[4][5] Podocalyxin is also upregulated in a number of cancers and is frequently associated with poor prognosis.[5][6] Sialylated, O-glycosylated glycoforms of podocalyxin expressed by colon carcinoma cells possess L-selectin and E-selectin binding activity, and may be pivotal to the metastatic spread of colon carcinoma cells.[7][8][9]

References

  1. ^ Omim - Podocalyxin-Like; Podxl
  2. ^ Nielsen JS, McNagny KM (2008). "Novel functions of the CD34 family". J of Cell Science 121 (Pt 22): 3682–3692. doi:10.1242/jcs.037507. PMID 18987355. 
  3. ^ Gartner, LP; Hiatt, Strum (2007). Cell Biology and Histology. Lippincott Williams and Wilkins. ISBN 978-0-7817-8577-8. 
  4. ^ Doyonnas R, Kershaw DB, Duhme C, Merkens H, Chelliah S, Graf T, McNagny KM (2001). "Anuria, Omphalocele, and Perinatal Lethality in Mice Lacking the Cd34-Related Protein Podocalyxin". J Exp Med 194 (1): 13–27. doi:10.1084/jem.194.1.13. PMC 2193439. PMID 11435469. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2193439. 
  5. ^ a b Nielsen JS, McNagny KM (2009). "The role of podocalyxin in health and disease". J Am Soc Nephrol 20 (10): 1669–76. doi:10.1681/ASN.2008070782. PMID 1957800. 
  6. ^ Somasiri A, Nielsen JS, Makretsov N, McCoy ML, Prentice L, Gilks CB, Chia SK, Gelmon KA, Kershaw DB, Huntsman DG, McNagny KM, Roskelley CD (2004). "Overexpression of the anti-adhesin podocalyxin is an independent predictor of breast cancer progression". Cancer Res 64 (15): 5068–73. doi:10.1158/0008-5472.CAN-04-0240. PMID 15289306. 
  7. ^ Thomas SN, Schnaar RL, Konstantopoulos K (Mar 2009). "Podocalyxin-like protein is an E-/L-selectin ligand on colon carcinoma cells: comparative biochemical properties of selectin ligands in host and tumor cells". Am J Physiol Cell Physiol 296 (3): C505–13. doi:10.1152/ajpcell.00472.2008. PMC 2660269. PMID 19118161. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2660269. 
  8. ^ Konstantopoulos K, Thomas SN (2009). "Cancer cells in transit: the vascular interactions of tumor cells". Annu Rev Biomed Eng 11: 177–202. doi:10.1146/annurev-bioeng-061008-124949. PMID 19413512. 
  9. ^ Thomas SN, Tong Z, Stebe KJ, Konstantopoulos K (2009). "Identification, characterization and utilization of tumor cell selectin ligands in the design of colon cancer diagnostics". Biorheology 46 (3): 207–25. doi:10.3233/BIR-2009-0534. PMID 19581728.