Int J Biochem Mol Biol 2011;2(3):263-273

Original Article
Evidence for phosphorylation in the MSP cytoskeletal filaments of amoeboid
spermatozoa

Juan J. Fraire-Zamora, Gina Broitman-Maduro, Morris Maduro, Richard A. Cardullo

Department of Biology, University of California, Riverside, CA 92521, USA.

Received April 8, 2011; accepted April 20, 2011; Epub April 22, 2011; Published AUgust 30, 2011

Abstract: Nematode spermatozoa are highly specialized cells that lack flagella and, instead, extend a pseudopod to initiate motility. Crawling
spermatozoa display classic features of amoeboid motility (e.g. protrusion of a pseudopod that attaches to the substrate and the assembly and
disassembly of cytoskeletal filaments involved in cell traction and locomotion), however, cytoskeletal dynamics in these cells are powered
exclusively by Major Sperm Protein (MSP) rather than actin and no other molecular motors have been identified. Thus, MSP-based motility is
regarded as a simple locomotion machinery suitable for the study of plasma membrane protrusion and cell motility in general. This recent
focus on MSP dynamics has increased the necessity of a standardized methodology to obtain C. elegans sperm extract that can be used in
biochemical assays and proteomic analysis for comparative studies.  In the present work we have modified a method to reproducibly obtain
relative high amounts of proteins from C. elegans sperm extract.  We show that these extracts share some of the properties observed in sperm
extracts from the parasitic nematode Ascaris including Major Sperm Protein (MSP) precipitation and MSP fiber elongation. Using this method
coupled to immunoblot detection, Mass Spectrometry identification, in silico prediction of functional domains and biochemical assays, our
results indicate the presence of phosphorylation sites in MSP of Caenorhabditis elegans spermatozoa. (IJBMB1107002)

Keywords: Major Sperm Protein, phosphorylation, cell motility, spermatozoa, C. elegans

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Address all correspondence to:
Dr. Juan J. Fraire-Zamora
Zentrum für Biosystemanalyse (ZBSA)
University of Freiburg
Habsburgerstrasse 49, 79104
Freiburg, Germany.
E-mail:  fraire-zamora@zbsa.de
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