Serine protease inhibitor Kazal-type 2 (SPINK2)

Serine protease inhibitor Kazal-type 2 (SPINK2) is a small, secreted protein primarily acting as a **trypsin and acrosin inhibitor** through a Kazal-type domain characterized by six cysteine residues forming three disulfide bridges[1][5]. SPINK2 is mainly expressed in the testis, epididymis, and seminal vesicle, where it is essential for normal spermiogenesis by neutralizing proteases during sperm maturation and preventing premature protease activation[5][6]. SPINK2 functions as a typical Kazal-type serine protease inhibitor, with a key role in **male fertility** and the regulation of proteolytic events during sperm development[5][1]. Elevated SPINK2 expression has been linked to improved prognosis in certain lymphomas and is a significant independent prognostic biomarker in acute myeloid leukemia (AML), where high expression is associated with altered immune cell infiltration and immune pathway activity[2]. Disruption or loss of SPINK2 can lead to fertility problems, while aberrant expression is linked to hematological malignancies and may influence the tumor microenvironment. There are currently no drugs that directly target SPINK2, and its main biological activity is through direct enzyme inhibition rather than receptor-mediated signaling[1][2][5].

Other names

Serine peptidase inhibitor Kazal type 2HUSI-IIAcrosin-trypsin inhibitorEpididymis tissue protein Li 172SPGF29SPINK2serine protease inhibitor Kazal-type 2acrosin-trypsin inhibitor

Inhibits serine proteases (primarily acrosin and trypsin) by direct binding to their catalytic sites, neutralizing their activity