A Novel Membrane Protein-Specific Serine/Threonine Kinase: Tissue Distribution and Role in Sperm Maturation

Abstract

<jats:p>Our recent studies have described for the first time the purification of an ectoprotein kinase to apparent homogeneity using caprine sperm as the model. Purified ectokinase (CIK) is a novel membrane protein-specific kinase that phosphorylates serine and threonine residues of ectophosphoproteins. This study, using ELISA based on ecto-CIK antibody demonstrates that ecto-CIK level is remarkably higher in the sperm membrane than in the cytosol. The epididymal sperm maturational event as well as sperm vertical velocity is associated with a significant increase in the ecto-CIK level. Ecto-CIK, the membrane protein-specific kinase, is also present in all the tissues tested and is predominantly localized in the cell membrane. Ubiquitous localization of the novel kinase on the mammalian cell membrane suggests that the kinase may play pivotal role in gamete as well as somatic cell regulation by modulating membrane biology through serine/threonine phosphorylation of specific membrane proteins located in the ectodomains.</jats:p>

Pengembangan Modul Berbasis Penelitian Analisis Aktivitas Fosforilasi Protein Membran Spermatozoa Kambing Untuk Matakuliah Teknik Analisis Biologi Molekuler

“…Jenis protein yang memiliki aktivitas fosforilasi pada protein 43 kDa diduga merupakan protein kinase. Nath et al (2012) menyatakan bahwa aktivitas fosforilasi protein kinase yang terdapat pada membran spermatozoa kambing berperan penting dalam menyediakan energi motilitas sperma. Urner & Sakkas (2003) menyatakan bahwa kemampuan sperma untuk melakukan motilitas progresif pada saat membuahi sel telur ditandai dengan adanya peningkatan aktivitas fosforilasi oleh protein tirosin kinase yang terjadi di bagian flagel atau ekor spermatozoa.…”