Regulation of YAP by mechanical strain through Jnk and Hippo signaling.

Mechanical forces affect all the tissues of our bodies. Experiments conducted mainly on cultured cells have established that altering these forces influences cell behaviors, including migration, differentiation, apoptosis, and proliferation [1, 2]. The transcriptional coactivator YAP has been identified as a nuclear relay of mechanical signals, but the molecular mechanisms that lead to YAP activation were not identified [3].

Hippo signaling goes long range.

The Hippo-YAP pathway regulates organ size by modulating cell proliferation and apoptosis. Yu et al. now reveal that G-protein-coupled receptors act upstream of the transcriptional coactivators YAP/TAZ.

p73 participates in male germ cells apoptosis induced by etoposide.

Etoposide is a commonly used drug in testicular cancer chemotherapy. However, the molecular pathways that activate germ cell apoptosis in response to etoposide are poorly understood. The aim of this study was to evaluate the participation of p73, a member of the p53 family, in apoptosis induced by etoposide in male germ cells.

A molecular evaluation of germ cell death induced by etoposide in pubertal rat testes.

Etoposide is widely used in the treatment of patients with testicular cancer. The mechanism underlying apoptosis induction in cancer cells has been studied in different cell types, but it is not known whether the same factors participate in viable germ cells undergoing programmed cell death. Since testicular cancer primarily affects young males, we used pubertal rats (21 days old) as a model to determine different apoptotic parameters after etoposide treatment in healthy testes.

Relevance of caspase activity during apoptosis in pubertal rat spermatogenesis.

Caspases are a family of cysteine-proteases, activated upon several different stimuli, which execute apoptosis in many cell death models. Previous work of our group has shown rats have the highest rate of apoptosis during the first wave of spermatogenesis (between 20 and 25 days after birth), as evaluated by TUNEL and caspase activity. However, the hierarchical order of caspase activation and the relevance of each caspase during germ cell apoptosis are not clear.

Inhibition of the vacuolar H(+)-pump with bafilomycin A1 does not induce acrosome reaction or activate proacrosin in mouse spermatozoa.

Acrosomal protease activation is regarded as an important event triggered by acrosomal reaction and leading to sperm passage through zona pellucida. Mammalian acrosome has an internal acid pH that probably helps to maintain inactive proenzymes that otherwise could be precociously activated and prevent normal fertilization. In this work, we have studied the effect of bafilomycin A1, a potent and specific inhibitor of vacuolar H(+)-pump (V-ATPase), on acrosome reaction and proacrosin activation.

Proacrosin/acrosin quantification as an indicator of acrosomal integrity in fresh and frozen dog spermatozoa.

The scope of the present study was to evaluate the presence and activation of proacrosin/acrosin as a tool to determine the acrosomal status of fresh and frozen/thawed dog spermatozoa. Monoclonal antibody C5F11, directed against human acrosin, cross-reacted with dog spermatozoa and labeled the acrosome of both fresh and frozen/thawed dog spermatozoa. Frozen/thawed spermatozoa had a lesser proportion of labeled spermatozoa than fresh spermatozoa (P<0.