Tubulobulbar complexes (TBCs), evaginations of mature spermatids, penetrate into the surrounding Sertoli cell cytoplasm of testis seminiferous epithelium during rat spermatogenesis. These structures prepare mature spermatids for their release into the seminiferous tubular lumen via a process called spermiation. Based on their functions of transient attachment and endocytosis, many actin-regulatory and endocytic proteins are associated with TBCs. Previously, exogenous 17β-estradiol administration to adult male rats showed spermiation failure that was attributed to TBC disruption. To determine the molecular basis of estrogen-induced TBC disruption, we examined the expressions and localizations of actin-regulatory proteins, endocytic proteins, Rho-GTPases, and phosphorylation in TBCs during sperm release. Results demonstrated absence of neural Wiscott Aldrich syndrome protein, cortactin, adaptor-related protein complex 2 sigma-1 subunit, dynamin 2, cell division control protein 42, and phosphocortactin in the concavity of spermatid head where TBCs are present without change in their protein expression levels. Absence of these proteins could have led to collapse of the TBC structure which is involved in its formation and function.
KimminsSKotajaNDavidsonISassone-CorsiP. Testis-specific transcription mechanisms promoting male germ-cell differentiation. Reproduction. 2004;128(1):5–12.
2.
LeblondCPClermontY.Definition of the stages of the seminiferous epithelium in the rat. Ann NY Acad Sci. 1952;55(4):548–573.
3.
HessRA. Quantitative and qualitative characteristics of the stages and transitions in the cycle of the rat seminiferous epithelium: light microscopic observations of perfusion-fixed and plastic-embedded testes. Biol Reprod. 1990;43(3):525–542.
4.
ClermontYLeblondCP.Spermiogenesis of man, monkey, ram and other mammals as shown by the “periodic acid-schiff” technique. Amer J Anat .1955;96(2):229–253.
5.
RussellLD. Further observations on tubulobulbar complexes formed by late spermatids and Sertoli cells in the rat testis. Anat Rec. 1979;194(2):213–232.
6.
VoglAWVaidKSGuttmanJA. The Sertoli cell cytoskeleton. Adv Exp Med Biol. 2008;636:186–211.
7.
GuttmanJATakaiYVoglAW.Evidence that tubulobulbar complexes in the seminiferous epithelium are involved with internalization of adhesion junctions. Biol Reprod .2004;71(2):548–559.
8.
LiePPChanAYMrukDDLeeWMChengCY. Restricted Arp3 expression in the testis prevents blood–testis barrier disruption during junction restructuring at spermatogenesis. Proc Natl Acad Sci U S A. 2010;107(25):11411–11416.
9.
O’DonnellLNichollsPKO’BryanMKMcLachlanRIStantonPG. Spermiation: the process of sperm release. Spermatogenesis .2011;1(1):1–22.
10.
YoungJSTakaiYKojicKLVoglAW. Internalization of adhesion junction proteins and their association with recycling endosome marker proteins in rat seminiferous epithelium. Reproduction. 2012;143(3):347–357.
11.
YoungJSGuttmanJAVaidKSShahinianHVoglAW. Cortactin (CTTN), N-WASP (WASL) and clathrin (CLTC) are present at podosome-like tubulobulbar complexes in the rat testis. Biol Reprod .2009;80(1):153–161.
12.
KusumiNWatanabeMYamadaHImplication of ampiphysin I and dynamin 2 in tubulobulbar complex formation and spermatid release. Cell Struct Funct .2007;32(2):101–113.
13.
AnaharaRYoshidaMToyamaYEstrogen agonists, 17beta-estradiol, bisphenol A, and diethylstilbestrol, decrease cortactin expression in the mouse testis. Arch Histol Cytol. 2006;69(2):101–107.
14.
HuangCNiYWangTGaoYHaudenschildCCZhanX. Down-regulation of the filamentous actin cross-linking activity of cortactin by src-mediated tyrosine phosphorylation. J Biol Chem. 1997;272(21):13911–13915.
15.
BalguerieASivadonPBonneuMAigleM. Rvs167p, the budding yeast homolog of amphiphysin, colocalizes with actin patches. J Cell Sci. 1999;112(pt 15):2529–2537.
16.
McNivenMAKimLKruegerEWOrthJDCaoHWongTW.Regulated interactions between dynamin and the actin-binding protein cortactin modulate cell shape. J Cell Biol. 2000;151(1):187–198.
17.
FordMGPearseBMHigginsMKSimultaneous binding of PtdIns(4,5)P2 and clathrin by AP180 in the nucleation of clathrin lattices on membranes. Science. 2001;291(5506):1051–1055.
18.
StylliSSKayeAHLockP.Invadopodia. At the cutting edge of tumour invesion. J. Clinical Neuroscience. 2008;15(7):725–737.
19.
ZigmondSHJoyceMYangCBrownKHuangM.Mechanism of Cdc42-induced actin polymerization in neutrophil extracts. J Cell Biol. 1998;142(4):1001–1012.
20.
WongEWMrukDDLeeWMChengCY. Regulation of blood–testis barrier dynamics by TGF-β3 is a Cdc42-dependent protein trafficking event. Proc Natl Acad Sci U S A. 2010;107(25):11399–11404.
21.
D’SouzaRGill-SharmaMKPathakSKediaNKumarRBalasinorN. Effect of high intratesticular estrogen on the seminiferous epithelium in adult male rats. Mol Cell Endocrinol. 2005;241(1-2):41–48.
22.
D’SouzaRPathakSUpadhyayRGaonkarRD’SouzaSSonawaneS. Disruption of tubolobulbar complex by high intratesticular estrogens leading to failed spermiation. Endocrinology. 2009;150(4):1861–1869.
23.
UpadhyayRD'SouzaRSonawaneSAltered phosphorylation and distribution status of vimentin in rat seminiferous epithelium following 17β-estradiol treatment. Histochem Cell Biol. 2011;136(5):543–555.
24.
LeblancJZhangXMcKeeDThe small GTPase Cdc42 promotes membrane protrusion during polar body emission via ARP2-nucleated actin polymerization. Molecular Human Reproduction. 2011;17(5):305–316.
25.
O'DonnellLMeachemSJStantonPGMcLachlanRI. Endocrine regulation of spermatogenesis. In: NeillJDPlantTMPfaffD W, eds. Physiology of Reproduction. San Diego, CA: Elsevier; 2006:1017–1069.
26.
SaitoKO’DonnellLMcLachlanRIRobertsonDM. Spermiation failure is a contributor to early spermatogenic suppression caused by hormone withdrawal in adult rats. Endocrinology. 2000;141(8):2779–2785.
27.
BeardsleyAO’DonnellL. Characterization of normal spermiation and spermiation failure induced by hormone suppression in adult rats. Biol Reprod. 2003;68(4):1299–1307.
28.
O’DonnellLPratisKWagenfeldATranscriptional profiling of the hormone-responsive stages of spermatogenesis reveals cell-, stage- and hormone-specific events. Endocrinology. 2009;150(11):5074–5084.
29.
BalasinorNHD’SouzaRNanawarePEffect of high intratesticular estrogen on global gene expression and testicular cell number in rats. Reprod Biol Endocrinol. 2010;8:72.
30.
OliveiraCMahechaGCarnesKDifferential hormonal regulation of estrogen receptors ERalpha and ERbeta and androgen receptor expression in rat efferent ductules. Reproduction. 2004;128(1):73–86.
31.
KaushikMCMisroMMSehgalNNandanD. AR versus ER (α) expression in the testis and pituitary following chronic estrogen administration in adult rat. Syst Biol Reprod Med. 2010;56(6):420–430.
32.
SanchezAMFlaminiMIFuXDRapid signaling of estrogen to WAVE1 and moesin controls neuronal spine formation via the actin cytoskeleton. Molecular Endocrinology. 2009;23(8):1193–1202.
33.
SuetsuguSMikiHTakenawaT. Identification of another actin-related protein (Arp) 2/3 complex binding site in neural Wiskott-Aldrich syndrome protein (N-WASP) that complements actin polymerization induced by the Arp2/3 complex activating (VCA) domain of N-WASP. J Biol Chem. 2001;276(35):3175–3180.
34.
Le ClaincheCCarlierMF.Regulation of actin assembly associated with protrusion and adhesion in cell migration. Physiol Rev. 2008;88(2):489–513.
35.
Cosen-BinkerLIKapusA. Cortactin: the gray eminence of the cytoskeleton. Physiology. 2006;21:352–361.
36.
MiyasoHKomiyamaMMatsunoYThe changes of cortactin p80/85 isoform profiles and tyrosine phosphorylation status during spermatogenesis in the mouse testis. J. Androl. 2010;31(5):507–518.
37.
TakeiKMcPhersonPSSchmidSLDe CamilliP. Tubular membrane invaginations coated by dynamin rings are induced by GTP-γS in nerve terminals. Nature. 1994;374(6518):186–190.
38.
KamitaniAYamadaHKinutaMDistribution of dynamins in testis and their possible relation to Spermatogenesis. Biochem Biophys Res Commun. 2002;294(2):261–267.
39.
OchoaGSlepnevVINeffLA functional link between dynamin and the actin cytoskeleton at podosomes. J Cell Biol. 2000;150(2):377–390.
40.
TebarFBohlanderSKSorkinA.Clathrin Assembly Lymphoid Myeloid Leukemia (CALM) Protein. Localization in endocytic-coated pits, interactions with clathrin, and the impact of overexpression on clathrin-mediated traffic. Mol Biol Cell. 1999;10(8):2687–2702.
41.
MullinsRDPollardTD.Rho-family GTPases require the Arp2/3 complex to stimulate actin polymerizationin Acanthamoeba extracts. Curr Biol. 1999;9(8):405–415.
