Table of Contents
ISRN Urology
Volume 2012, Article ID 789105, 7 pages
Research Article

A Novel Membrane Protein-Specific Serine/Threonine Kinase: Tissue Distribution and Role in Sperm Maturation

1Cell Biology & Physiology Division, Indian Institute of Chemical Biology, Jadavpur, Kolkata 700032, India
2Department of Zoology, University of Kalyani, Kalyani 743215, India
3Cryobiology Department, Centre for Rural and Cryogenic Technologies, Jadavpur University, Kolkata 700032, India

Received 10 November 2011; Accepted 5 December 2011

Academic Editors: E. Bustos-Obregon and B. Delahunt

Copyright © 2012 Debjani Nath et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Our recent studies have described for the first time the purification of an ectoprotein kinase to apparent homogeneity using caprine sperm as the model. Purified ectokinase (CIK) is a novel membrane protein-specific kinase that phosphorylates serine and threonine residues of ectophosphoproteins. This study, using ELISA based on ecto-CIK antibody demonstrates that ecto-CIK level is remarkably higher in the sperm membrane than in the cytosol. The epididymal sperm maturational event as well as sperm vertical velocity is associated with a significant increase in the ecto-CIK level. Ecto-CIK, the membrane protein-specific kinase, is also present in all the tissues tested and is predominantly localized in the cell membrane. Ubiquitous localization of the novel kinase on the mammalian cell membrane suggests that the kinase may play pivotal role in gamete as well as somatic cell regulation by modulating membrane biology through serine/threonine phosphorylation of specific membrane proteins located in the ectodomains.