This Article Full Text Full Text (PDF) All Versions of this Article: 27/3/390    most recent Author Manuscript (PDF) Author Manuscript (PDF) Author Manuscript (PDF) Author Manuscript (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Heydecke, D. Articles by Boekhoff, I. Search for Related Content PubMed PubMed Citation Articles by Heydecke, D. Articles by Boekhoff, I.

The Multi PDZ Domain Protein MUPP1 as a Putative Scaffolding Protein for Organizing Signaling Complexes in the Acrosome of Mammalian Spermatozoa

DIANA HEYDECKE^*,

DORKE MEYER^*,

BEATE WILHELM

From the Departments of ^* Pharmacology and Toxicology and Anatomy and Cell Biology, Philipps-University Marburg, Germany.

Correspondence to: Ingrid Boekhoff, Philipps-University Marburg, Department of Pharmacology and Toxicology, Karl-von-Frisch-Straße 1, D-35033 Marburg, Germany (e-mail: boekhoff{at}staff.uni-marburg.de).

Spermatozoa undergo complex sequences of precisely timed events during the process of fertilization. These priming events, which comprise capacitation, egg recognition, acrosome reaction, and sperm-oocyte fusion, are regulated by the activation of different intracellular signaling pathways. The efficacy and accuracy of signal transduction pathways often depend on the assembly of multiprotein signaling complexes, thereby coordinating and guiding the flow of regulatory information. To address the question whether PDZ-domain proteins, the most abundant protein interaction modules involved in the assembly of supramolecular signaling complexes, are present in rodent sperm, homologue of the RT-PCR approaches were performed with specific primer pairs for the vertebrate INAD-like PDZ domain protein MUPP1. The results revealed that this scaffolding protein, which comprises 13 different PDZ domains, is expressed in mouse testis. To obtain further support for the expression of the multi-PDZ domain protein MUPP1 in testicular tissue, immunohistochemical as well as immunocytochemical experiments were performed using a MUPP1-specific antibody. Detailed analyses of the spatial MUPP1-expression profile revealed that immunoreactivity is concentrated within the acrosomal region of round as well as elongated mouse spermatozoa. These results were confirmed in experimental approaches demonstrating that MUPP1 immunofluorescence was shed off from the acrosome region after acrosome reaction. To examine whether MUPP1 is also present in other mammalian sperm, immunocytochemical approaches were performed with isolated bovine as well as human sperm. The results revealed prominent MUPP1 expression which was restricted to the apical acrosomal region and, most notably, to the equatorial segment of the acrosome. The predominant expression profile of MUPP1 in sperm of different mammalian species suggests that this PDZ-domain protein may be involved in organizing signaling molecules mediating primary reactions of fertilization.

     Key words: Signal transduction, acrosome reaction, MPDZ

This article has been cited by other articles:

				M. A. Lanaspa, A. Andres-Hernando, C. J. Rivard, Y. Dai, and T. Berl Hypertonic stress increases claudin-4 expression and tight junction integrity in association with MUPP1 in IMCD3 cells PNAS, October 14, 2008; 105(41): 15797 - 15802. [Abstract] [Full Text] [PDF]