Novel actin-related proteins Arp-T1 and Arp-T2 as components of the cytoskeletal calyx of the mammalian sperm head.
The calyx is a large cytoskeletal component of the perinuclear theca of the mammalian sperm head, displaying remarkable morphological interspecies differences, which is biochemically characterized by resistance to high ionic strength and detergents and by a special protein composition, including the basic proteins calicin, cylicin I and II, and two major actin-capping proteins. In our calyx preparations from bull spermatozoa we have noted two major acidic components which upon partial amino acid sequencing have been identified as novel members of the subfamily of actin-related proteins (Arps). Antibodies raised against the corresponding human proteins, termed Arp-T1 and Arp-T2, have been used to detect the proteins by immunoblotting and immunofluorescence microscopy, demonstrating their specific synthesis in the testis, late in spermatid differentiation, and their localization in the calyx. The discovery of two novel Arps as major components in a cytoskeletal, nonmotile structure of mammalian spermatozoa suggests that certain members of this family of proteins may serve functions other than nucleation of actin filaments, and possible biological roles of such Arps in spermatozoa are discussed.
Heid
Hans
H
Division of Cell Biology, German Cancer Research Center, D-69120, Heidelberg, Germany. hheid@dfz.de
Figge
Ulrike
U
Winter
Stefanie
S
Kuhn
Caecilia
C
Zimbelmann
Ralf
R
Franke
Werner
W
D051377:Actin-Related Protein 2; D000199:Actins / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000378:metabolism; D002417:Cattle; D002458:Cell Fractionation; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism*; D006801:Humans; D008297:Male; D008840:Microfilament Proteins; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013094:Spermatozoa / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D014018:Tissue Distribution; D018909:src Homology Domains
C495926:ACTR2 protein, human; C107063:ACTRT1 protein, human; D051377:Actin-Related Protein 2; D000199:Actins; C491476:Actrt1 protein, mouse; D000906:Antibodies; D003598:Cytoskeletal Proteins; C117063:DBNL protein, human; D008840:Microfilament Proteins; D010455:Peptides; D011994:Recombinant Proteins