Table 5.

Testis-Specific Proteins and Isoforms from the Trx Family

Protein isoform	Cell types	Specific properties	Reference(s)
mouse Grx2c and Grx2d	Spermatogonia, spermatids	Unlike Grx2c, Grx2d is inactive and does not form iron-sulfur cluster bridged dimers	(310)
human Grx2b and Grx2c	Spermatids, Sertoli cells, cancer cells	Unlike Grx2c, Grx2b does not form iron-sulfur cluster bridged dimers	(447)
TXNRD1_v3	Leydig cells, cancer cells	TXNRD1_v3 guides actin polymerization in relation to cell membrane restructuring	(144)
TGR and TGR-1	Elongating spermatids	CUG serves as an inefficient start codon in mouse and rat	(224, 744)
TXNDC2/Sp-Trx1	Spermatids	Nucleation center in fibrous sheath (suspected)	(498)
TXNDC3/Sp-Trx2	Spermatids	Structural component of fibrous sheath (suspected)	(663)
TXNDC8/Sp-Trx3	Spermatids	Likely required in later steps of spermiogenesis or mature spermatozoa	(345)
Txl-2	Mainly associated with cilia and flagella	Novel regulator of microtubule physiology (suspected)	(664)
snGPx	Spermatocytes and early spermatids	Restricted to late stages of spermatogenesis	(515)
Prx4 31kda	Membrane bound in the elongating spermatid and the residual body	Acrosome formation during vesicular reorganization in spermiogenesis	(558, 679)