Identification of phosphatases on the membranes of guinea pig sperm

Abstract

Guinea pig epididymal sperm, incubated for ATPases at pH 7.0 or pH 9.0, localize reaction product on both the periacrosomal segment of the plasmalemma and the outer acrosome membrane. In other species, e.g., rabbit, Ca++-ATPase is identified with the outer acrosome membrane. It may transport Ca++ into the acrosome for activation of enzymes released during the acrosome reaction. The neutral ATPase is demonstrable on the periacrosomal plasmalemma and possibly modifies Ca++ concentration in the fluid around the acrosome. In guinea pig sperm, Ca++-ATPase is sensitive to centrifugation or washing of sperm which indicates that the ductal fluid has unusual properties for preservation of the acrosome. Inhibition of the enzyme by these treatments suggests that conditions on the plasmalemmal surface affect the acrosome membrane. Inability to separate reaction product on the plasmalemma from that on the acrosome membrane may be due to migration of reaction product across the periacrosomal space. However, the ATPases are elicited in the guinea pig under the same conditions as in other species. The pH 9.0 enzyme requires Ca++ while the enzyme at pH 7.0 has no ion specificities. Demonstration of these enzymes indicates that mechanisms of acrosome activation, similar to those in other sperm, are relevant to the guinea pig.

Maintenance of Motility in Mouse Sperm Permeabilized with Streptolysin O1

“…The requirement for a preincubation in a Ca 2ϩ -containing medium could indicate that there are changes at the plasma membrane level that allow the SLO to interact with cholesterol and form pores [44][45][46]. Although Díaz et al [22] demonstrated that mouse sperm can be permeabilized by SLO in the absence of a preincubation, the sperm in their protocol were washed with a hypertonic buffer prior to SLO treatment.…”

Requirement of extracellular calcium ions for various stages of fertilization and fertilization‐related phenomena in the hamster

“…It is not fully understood how intracellular Ca2+ induces or promotes the fusion between the outer acrosomal and the overlying sperm plasma membranes. Ca2+ accumulated between these two membranes may induce the fusion of the membranes directly and/or indirectly via a complicated series of chemical reactions [Gordon, 1973;Gordon et al, 1978;Green, 1978b;Meizel, 1978;Lui and Meizel, 1979;Hyne and Garbers, 1979;Yanagimachi, 1981b;Fleming and Yanagimachi, 19811.…”

A study of cAMP binding proteins on intact and disrupted sperm cells using 8‐azidoadenosine 3′,5′‐cyclic monophoshate

“…Recently Brandt and Hoskins [19] reported a relationship between cell motility and the CAMP-dependent phosphorylation of a protein in bovine epididymal sperm, but other functions of CAMPdependent protein kinases in sperm metabolism are unknown, as are further relationships between kinases and the CAMP-mediated physiological events mentioned above. Externally facing ATPases [20,21] and protein kinases [ 16,171 have been reported in sperm and other cells [22-241. Stephens et a1 [25] have speculated that one of the multiple forms of spermatozoan phosphodiesterases may also be external. This leads to the obvious question concerning the membrane sidedness of CAMP-binding proteins of sperm and their comparison to the known cAMP receptor sites of CAMP-activated types I and I1 kinases.…”