HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 278, Issue 52, 52673-52680, December 26, 2003

This Article Full Text Full Text (PDF) All Versions of this Article: 278/52/52673    most recent M308365200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ullas, K. S. Articles by Rao, M. R. S. Search for Related Content PubMed PubMed Citation Articles by Ullas, K. S. Articles by Rao, M. R. S. Social Bookmarking                      What's this?

Phosphorylation of Rat Spermatidal Protein TP2 by Sperm-specific Protein Kinase A and Modulation of Its Transport into the Haploid Nucleus^*

Kolthur S. Ullas and Manchanahalli R. S. Rao

From the Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India

Transition protein 2 (TP2), which is expressed during stages 12–15 of mammalian spermiogenesis, has been shown to undergo phosphorylation immediately after its synthesis. We reported earlier that TP2 is phosphorylated in vitro at threonine 101 and serine 109 by the salt extract of sonication-resistant (elongating and elongated) spermatid nuclei and the protein kinase phosphorylating TP2 was identified to be protein kinase A (PKA). We now report that the cytosol from haploid spermatids but not from premeiotic germ cells is able to phosphorylate recombinant TP2 in vitro at threonine 101 and serine 109. The kinase present in the haploid spermatid cytosol that phosphorylates TP2 has been identified to be the sperm-specific isoform of protein kinase A (Cs-PKA). Reverse transcription-PCR analysis indicated that Cs-PKA was present in the haploid spermatids and absent from premeiotic germ cells. The rat Cs-PKA transcript was amplified and sequenced using the isoform-specific primers. The sequence of rat Cs-PKA at the N terminus differs from mouse and human by one amino acid. Western blot analysis using specific anti-C1 antibodies revealed that C1-PKA is absent in haploid spermatid cytosol. We have also established an in vitro nuclear transport assay for the haploid round spermatids. Using this assay, we have found that the cytoplasmic factors and ATP are absolutely essential for translocation of TP2 into the nucleus. Phosphorylation was found to positively modulate the NLS dependent import of TP2 into the nucleus.

Received for publication, July 31, 2003 , and in revised form, September 24, 2003.

The nucleotide sequence(s) reported in this paper has been submitted to the GenBank^TM/EBI Data Bank with accession number(s) AY375243.

^* This work was financially supported from grants from the Department of Biotechnology, New Delhi.

To whom correspondence should be addressed: Prof. M. R. S. Rao, Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India. Tel.: 91-80-2932547; Fax: 91-80-3000118; E-mail: mrsrao{at}biochem.iisc.ernet.in.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				B. Sarg, S. Chwatal, H. Talasz, and H. H. Lindner Testis-specific Linker Histone H1t Is Multiply Phosphorylated during Spermatogenesis: IDENTIFICATION OF PHOSPHORYLATION SITES J. Biol. Chem., February 6, 2009; 284(6): 3610 - 3618. [Abstract] [Full Text] [PDF]

				M. M. Pradeepa, S. Manjunatha, V. Sathish, S. Agrawal, and M. R. S. Rao Involvement of Importin-4 in the Transport of Transition Protein 2 into the Spermatid Nucleus Mol. Cell. Biol., July 1, 2008; 28(13): 4331 - 4341. [Abstract] [Full Text] [PDF]

				N. Kotaja, B. Macho, and P. Sassone-Corsi Microtubule-independent and Protein Kinase A-mediated Function of Kinesin KIF17b Controls the Intracellular Transport of Activator of CREM in Testis (ACT) J. Biol. Chem., September 9, 2005; 280(36): 31739 - 31745. [Abstract] [Full Text] [PDF]

				C.-H. Tsai-Morris, Y. Sheng, E. Lee, K.-J. Lei, and M. L. Dufau Gonadotropin-regulated testicular RNA helicase (GRTH/Ddx25) is essential for spermatid development and completion of spermatogenesis PNAS, April 27, 2004; 101(17): 6373 - 6378. [Abstract] [Full Text] [PDF]