High impact information on ADAM2

• The gene (MDC) encodes a 524-amino acid metalloprotease-like, disintegrin-like and cysteine-rich protein with sequence similarity to members of the snake-venom metalloprotease/disintegrin family and guinea-pig sperm-surface protein PH-30 [1].
• Because alpha6beta1 is present on murine eggs and interacts with the sperm-surface glycoprotein ADAM 2 (fertilin beta), we first asked whether CD9 is present on murine eggs and whether it functions in sperm-egg binding and fusion [2].
• We propose that the active sites of the PH-30 alpha and snake venom metalloproteases are structurally similar to that of astacin [3].
• Fertilin beta (also known as ADAM2) participates in sperm-egg membrane binding, and it has long been hypothesized that this function is achieved through the interaction of the disintegrin domain of fertilin beta with an integrin on the egg surface [4].
• We found that the ADAM2 and 15 disintegrin domains bound to oocytes, but the ADAM17 disintegrin domain did not [5].

Biological context of ADAM2

• Therefore, the ADAM1/ADAM2 heterodimer is visualized far in advance of the meiotic and spermiogenic phase of spermatogenesis [6].
• Comparison of amino acid sequences showed that ADAM32 is highly homologous to ADAM2 and ADAM3, sperm surface proteins required for fertilization [7].
• Apexin and a sperm protein related to complement receptors coelute with affinity-purified fertilin (PH-30), a potential sperm-egg membrane fusion protein [8].

Anatomical context of ADAM2

• In contrast, the expression of the ADAM1/ADAM2 pair (fertilin alpha/fertilin beta, respectively) is not detected in fetal testis [6].
• The precursors of ADAM1a and ADAM1b formed a heterodimeric complex with that of ADAM2 in the endoplasmic reticulum of germ cells [9].
• These results are consistent with the reported speculation [Blobel, C. P. et al. (1992), Nature (London) 356, 248-252] that residues 90-111 of PH-30 alpha may be the fusogenic region and suggest that the Pro-Pro sequence is one of the important factors for holding the active secondary structure of the fusogenic region of PH-30 alpha in membranes [10].
• The site of fusion on the sperm head is discussed, together with the evidence that PH-30 is the fusion protein [11].

Associations of ADAM2 with chemical compounds

• In the disintegrin region, the Arg-Gly-Asp sequence is replaced by Glu-Cys-Asp, as found in non-Arg-Gly-Asp disintegrin regions of HR1B and a guinea pig sperm fusion protein PH-30 beta [12].

Other interactions of ADAM2

• The most encouraging leads have come from groups using monoclonal antibodies to identify and characterize sperm antigens important for fertility (e.g. SP-10, PH-20 and PH-30) [13].

Analytical, diagnostic and therapeutic context of ADAM2

• Molecular cloning of the human fertilin beta subunit [14].

References