Coordinated and compartmentalized functions of CAII and CAIV establish a dual pH-regulatory mechanism essential for sperm maturation and capacitation.

ABSTRACT: The intracellular carbonic anhydrase II (CAII) and GPI-anchored extracellular carbonic anhydrase IV (CAIV) are distinctly compartmentalized enzymes that regulate bicarbonate (HCO₃ ^-) and acid-base homeostasis. Located in the epithelial cells of the epididymis, vas deferens, and on spermatozoa, these enzymes are positioned to regulate the pH environment critical for sperm maturation and capacitation, crucial for male reproduction. This regulation is essential for early sperm activation, as bicarbonate (HCO₃ ^-) triggers the soluble adenylyl cyclase (sAC)/cAMP signaling pathways and leads to an increase in intracellular pH (pH_i), a prerequisite for motility. However, the specific contributions of CAII and CAIV to luminal pH and to sperm p

SUBMITTER: Wiesehofer C 

PROVIDER: S-EPMC12632950 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature