Stage-specific expression of dynein light chain-1 and its interacting kinase, p21-activated kinase-1, in rodent testes: implications in spermiogenesis.
Mammalian spermatogenesis is a complex process involving regulatory interactions of many gene products. In this study, we found that dynein light chain-1 (DLC1), a component of the dynein motor complex, is highly expressed in mouse and rat testes. Immunohistochemically detectable levels of DLC1 are observed specifically in spermatids in steps 9-16 in distinct subcellular compartments: in steps 9-11, DLC1 is predominantly localized in the nucleus; in steps 12 and 13, it is found in both nucleus and cytoplasm; and in step 14-16, it is present exclusively in the cytoplasm. In addition, we found p21-activated kinase 1 (Pak1), a protein kinase that activates DLC1 by phosphorylating DLC1 at Serine 88, was also expressed during these stages of spermatogenesis. Pak1 was also expressed in Leydig cells, in preleptotene primary spermatocytes, and in round spermatids. The spermiogenic stage-specific expression of DLC1 suggests a role for DLC1 in chromatin condensation, spermatid shaping, and the final release of sperm from the spermatogenic epithelium. Further, Pak1 may also play a role in spermiogenesis by regulating DLC1 phosphorylation and, consequently, its function.
Department of Molecular and Cellular Oncology. UT-MD Anderson Cancer Center, Houston, TX 77030, USA.
Rui-An
RA
Wang
Ming
M
Zhao
Marvin L
ML
Meistrich
Rakesh
R
Kumar
D000818:Animals; D000831:Animals, Newborn; D019556:COS Cells; D002522:Chlorocebus aethiops; D051786:Cyclic AMP Response Element Modulator; D004268:DNA-Binding Proteins / Q000378:metabolism; D004398:Dyneins / Q000096:biosynthesis*; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000096:biosynthesis; D008297:Male; D051379:Mice; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis*; D051381:Rats; D013045:Species Specificity; D013091:Spermatogenesis; D013737:Testis / Q000201:enzymology* / Q000254:growth & development; D014157:Transcription Factors / Q000378:metabolism; D054462:p21-Activated Kinases
D004268:DNA-Binding Proteins; D007527:Isoenzymes; D014157:Transcription Factors; D051786:Cyclic AMP Response Element Modulator; C515905:Pak1 protein, mouse; C515906:Pak1 protein, rat; D017346:Protein Serine-Threonine Kinases; D054462:p21-Activated Kinases; D004398:Dyneins