Calsperin is a testis-specific chaperone required for sperm fertility
Masahito Ikawa1, Keizo Tokuhiro, Ryo Yamaguchi
1Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan. ikawa@biken.osaka-u.ac.jp
The Journal of Biological Chemistry
|December 7, 2010
Summary
Calreticulin-3 (CALR3) is essential for male fertility, despite normal sperm production. It ensures proper sperm function by aiding in the maturation of key proteins required for fertilization.
Area of Science:
- Reproductive biology
- Molecular chaperones
- Endoplasmic reticulum function
Background:
- Calnexin (CANX) and calreticulin (CALR) are endoplasmic reticulum chaperones crucial for glycoprotein folding.
- Calmegin (CLGN) and calsperin (CALR3) are germ cell-specific counterparts in the testis.
Purpose of the Study:
- To investigate the role of calsperin (CALR3) in male fertility.
- To elucidate the mechanism by which CALR3 influences sperm function and fertilization.
Main Methods:
- Generation and analysis of Calr3 knockout mice (Calr3(-/-)).
- Assessment of sperm motility, migration, binding to the zona pellucida, and protein maturation.
- Comparative analysis with calmegin (CLGN) function.
Main Results:
- Calr3(-/-) male mice produced morphologically normal sperm but exhibited infertility.
- Defective sperm migration into the oviduct and impaired binding to the zona pellucida were observed in Calr3(-/-) males.
- CALR3, a lectin-deficient chaperone, is directly required for the maturation of ADAM3, a critical sperm membrane protein.
Conclusions:
- Germ cell-specific endoplasmic reticulum chaperones CALR3 and CLGN have distinct roles in male fertility.
- CALR3 is essential for ADAM3 maturation and subsequent male fertility.
- Understanding these maturation mechanisms offers potential for novel contraceptive and infertility treatments.
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