Spermatid manchette: plugging proteins to zero into the sperm tail.
Spermiogenesis pursues three major objectives: (1) The safeguard of the male genome within the confines of a compact nucleus. (2) The accumulation of enzymes in the acrosome of be released at fertilization. (3) The development of a sperm propelling tail consisting of an axoneme surrounded by a scaffold of keratin-containing outer dense fibers and a fibrous sheath. Recent experimental data indicate that three keratins-Sak57, 0df1 and 0df2-and other proteins (the 26S proteasome and the 0df1-binding protein Spag4) are temporarily stored in the manchette before being sorted to the developing sperm tail. These findings support a general model for the manchette as an ephemeral structure timely developed and strategically positioned to provide a transient storage to both structural and signaling proteins. Some of the proteins are later sorted to the developing tail; others may participate in the reciprocal nuclear-cytoplasmic signaling pathways as the gene activity of the male genome gradually becomes silent. Mol. Reprod. Dev. 59: 347-349, 2001.
Kierszenbaum
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Department of Cell Biology and Anatomical Sciences, The City University of New York Medical School, 138th Street and Convent Avenue, New York, NY 10031, USA. kier@med.cuny.edu
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D007633:Keratins / Q000378:metabolism*; D008297:Male; D011506:Proteins / Q000378:metabolism; D013082:Sperm Tail / Q000502:physiology* / Q000648:ultrastructure; D013091:Spermatogenesis / Q000502:physiology*
D002352:Carrier Proteins; D011506:Proteins; D007633:Keratins