Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]
Volume 27: 1715 -1726. Published March 8, 2010.
Biochemical characterization of the mechanism of binding of a regulatory protein to the spermatozoa- specific protein phosphatase in Swiss Albino Ratntibiotic resistance patterns of Escherichia coli is
Surabhi Nanda*, V.P. Varshney** and Sanjay Mishra*
*Department of Biotechnology, College of Engineering and Technology, IFTM Campus, Moradabad, UP, India; **Physiology & Climatology Division, Indian Veterinary Research Institute, Izatnagar 243112, U.P., India.
*Author for correspondence e-mail: sanjaymishra66@gmail.com
ABSTRACT
Objective: The germ cell/tissue- specific Protein phosphatase, PP1γ2, plays a pivotal role in sperm function. Its activity gets reduced during sperm maturation in the epididymis. Inhibition of PP1γ2 results in motility initiation and stimulation. The aim of the present study was to determine the biochemical mechanism of PP1γ2-sds22 binding in reference to motility status of Swiss albino rat spermatozoa.
Methodology and results: The enzyme from caudal and caput sperm extracts was purified by column chromatography. PP1γ2 from caudal spermatozoa was inactive, whereas in caput spermatozoa it was active. The DEAE-cellulose flow through fractions was next passed through an SP-sepharose column. Caudal sperm sds22 and PP1γ2 were co-eluted in the gradient fraction. In contrast, caput sperm sds22 and PP1γ2 were separated in the flow-through and gradient fractions, respectively. Further purification through a Superose 6 column showed that PP1γ2-sds22 complex from caudal sperm was about 80 kDa in size. Caput sperm sds22 and PP1γ2 were observed to be eluted at 65 kDa and 39 kDa, respectively. SDS-PAGE of these purified fractions revealed that in caudal sperm, the 80 kDa species is composed of sds22 (43 kDa) and PP1γ2 (39 kDa), suggesting an equal ratio complex between these two key proteins. PP1γ2 bound to sds22 in this complex was observed to be inactive.Conclusion and application of findings: The results indicate that dissociation of sds22 from apparently 22 kDa protein is required for its binding and inactivation of PP1γ2. Further studies to determine the mechanisms responsible for development of sds22 binding to PP1γ2 during epididymal sperm maturation are in progress.
Key words: Phosphatases, signal transduction, sperm maturation, Swiss albino rat, testis.
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