The Microtubule Plus End Tracking Protein TIP150 Interacts with Cortactin to Steer Directional Cell Migration.

Cell migration is orchestrated by dynamic interactions of microtubules with the plasma membrane cortex. How these interactions facilitate these dynamic processes is still being actively investigated. TIP150 is a newly characterized microtubule plus end tracking protein essential for mitosis and entosis (Ward, T.

Prohibitin regulates the FSH signaling pathway in rat granulosa cell differentiation.

Published results from our laboratory identified prohibitin (PHB), a gene product expressed in granulosa cells (GCs) that progressively increases during follicle maturation. Our current in vitro studies demonstrate that follicle-stimulating hormone (FSH) stimulates Phb expression in rat primary GCs. The FSH-dependent expression of PHB was primarily localized within mitochondria, and positively correlates with the morphological changes in GCs organelles, and synthesis and secretions of estradiol (E2) and progesterone (P4).

Prohibitin( PHB) roles in granulosa cell physiology.

Ovarian granulosa cells (GC) play an important role in the growth and development of the follicle in the process known as folliculogenesis. In the present review, we focus on recent developments in prohibitin (PHB) research in relation to GC physiological functions. PHB is a member of a highly conserved eukaryotic protein family containing the repressor of estrogen activity (REA)/stomatin/PHB/flotillin/HflK/C (SPFH) domain (also known as the PHB domain) found in diverse species from prokaryotes to eukaryotes.

The spatiotemporal dynamics of chromatin protein HP1α is essential for accurate chromosome segregation during cell division.

Heterochromatin protein 1α (HP1α) is involved in regulation of chromatin plasticity, DNA damage repair, and centromere dynamics. HP1α detects histone dimethylation and trimethylation of Lys-9 via its chromodomain. HP1α localizes to heterochromatin in interphase cells but is liberated from chromosomal arms at the onset of mitosis.

Prohibitins role in cellular survival through Ras-Raf-MEK-ERK pathway.

Prohibitins are members of a highly conserved protein family containing the stomatin/prohibitin/flotillin/HflK/C (SPFH) domain (also known as the prohibitin [PHB] domain) found in unicellular eukaryotes, fungi, plants, animals, and humans. Two highly homologous members of prohibitins expressed in eukaryotes are prohibitin (PHB; B-cell receptor associated protein-32, BAP-32) and prohibitin 2/repressor of estrogen receptor activity (PHB2, REA, BAP-37). Both PHB and REA/PHB2 are ubiquitously expressed and are present in multiple cellular compartments including the mitochondria, nucleus, and the plasma membrane.

Prohibitin (PHB) inhibits apoptosis in rat granulosa cells (GCs) through the extracellular signal-regulated kinase 1/2 (ERK1/2) and the Bcl family of proteins.

Mammalian ovarian follicular development is tightly regulated by crosstalk between cell death and survival signals, which include both endocrine and intra-ovarian regulators. Whether the follicle ultimately ovulates or undergoes atresia is dependent on the expression and actions of factors promoting follicular cell proliferation, differentiation or apoptosis. Prohibitin (PHB) is a highly conserved, ubiquitous protein that is abundantly expressed in granulosa cells (GCs) and associated with GC differentiation and apoptosis.

The emerging roles of prohibitins in folliculogenesis.

Prohibitins are members of a highly conserved eukaryotic protein family containing the stomatin/prohibitin/flotillin/HflK/C (SPFH) domain (also known as the prohibitin (PHB) domain) found in divergent species from prokaryotes to eukaryotes. Prohibitins are found in unicellular eukaryotes, fungi, plants, animals and humans. Prohibitins are ubiquitously expressed and present in multiple cellular compartments including the mitochondria, nucleus, and the plasma membrane, and shuttles between the mitochondria, cytosol and nucleus.

Sperm GIRK2-containing K+ inward rectifying channels participate in sperm capacitation and fertilization.

The GIRK2-containing inward-rectifying K(+) ion channels have been implicated in mammalian spermatogenesis. While the Girk2 null mice are fertile, the male weaver transgenic mice carrying a gain-of-function mutation in the Girk2 gene are infertile. To establish the exact period of spermatogenesis affected by this mutation, we performed StaPut isolation and morphological characterization of the germ cells present in the weaver testis.

Prohibitin (PHB) acts as a potent survival factor against ceramide induced apoptosis in rat granulosa cells.

Aim: Ceramide is a key factor in inducing germ cell apoptosis by translocating from cumulus cells into the adjacent oocyte and lipid rafts through gap junctions. Therefore studies designed to elucidate the mechanistic pathways in ceramide induced granulosa cell (GC) apoptosis and follicular atresia may potentially lead to the development of novel lipid-based therapeutic strategies that will prevent infertility and premature menopause associated with chemo and/or radiation therapy in female cancer patients. Our previous studies have shown that Prohibitin (PHB) is intimately involved in GCs differentiation, atresia, and luteolysis.

Developmental patterns of PPAR and RXR gene expression during spermatogenesis.

Members of the family of nuclear receptors that include peroxisome proliferator-activated receptors (PPARs) and retinoid X receptors (RXRs) are important mediators of selective gene activation during development and cellular differentiation. In this study, developmentally-specific PPAR and RXR patterns of expression that occur in somatic and germ cell populations in the testis were determined using quantative real-time PCR (qRT-PCR) studies on RNAs that were isolated from StaPut purified mouse germ cells and primary rat Sertoli cells. These qRT-PCR studies indicate that transcripts encoding the PPAR-Alpha (α), -Beta (β), and -Gamma (γ) and RXR -Alpha (α), -Beta (β), and -Gamma (γ) are developmentally expressed in both differentiating germ and Sertoli cells.

PinX1 is a novel microtubule-binding protein essential for accurate chromosome segregation.

Mitosis is an orchestration of dynamic interactions between spindle microtubules and chromosomes, which is mediated by protein structures that include the kinetochores, and other protein complexes present on chromosomes. PinX1 is a potent telomerase inhibitor in interphase; however, its function in mitosis is not well documented. Here we show that PinX1 is essential for faithful chromosome segregation.

Molecular and functional characterization of the murine ldh2 promoter region: Sp-binding GC-box domains are the key cis-elements regulating ldh2 gene expression during spermatogenesis.

The goal of the present study was to elucidate the specific transcriptional mechanisms that regulate ldh2 gene expression during the early stages of spermatogenesis. DNA sequence analysis of the 1.0-kb ldh2 promoter region directly upstream of the transcriptional start site indicated the presence of three SP-protein binding GC-box elements and the absence of TATA and CAAT boxes.

Prohibitin silencing reverses stabilization of mitochondrial integrity and chemoresistance in ovarian cancer cells by increasing their sensitivity to apoptosis.

Current approaches to the treatment of ovarian cancer are limited because of the development of resistance to chemotherapy. Prohibitin (Phb1) is a possible candidate protein that contributes to development of drug resistance, which could be targeted in neoplastic cells. Phb1 is a highly conserved protein that is associated with a block in the G0/G1 phase of the cell cycle and also with cell survival.

SP1 transcription factors in male germ cell development and differentiation.

Transcription factor SP1 is a zinc finger protein that has been implicated in regulating the expression of several genes involved in cellular differentiation and embryonic development. The zinc finger region of SP1 transcription factors binds to GC or GT-box elements present in the promoters of a number of male germ cell target genes that are developmentally expressed during spermatogenesis. The glutamine and serine/threonine-rich regions of the SP1 proteins recruit co-regulatory factors to the multi-protein preinitiation complex that are important for mediating transcriptional activation in male germ cells.

Apoptosis of rat granulosa cells after staurosporine and serum withdrawal is suppressed by adenovirus-directed overexpression of prohibitin.

Prohibitin (Phb1) is a highly conserved mitochondrial protein that is associated with granulosa cell differentiation, atresia, and luteolysis. Although prohibitin has been implicated in the suppression of apoptosis in mammalian cells, its specific role in programmed cell death in granulosa cells is unknown. In the present study, we examined the role of prohibitin in mediating staurosporine (STS) and serum withdrawal induced apoptosis in undifferentiated rat granulosa cells.

Identification, characterization, and functional analysis of sp1 transcript variants expressed in germ cells during mouse spermatogenesis.

The SP family of zinc-finger transcription factors are important mediators of selective gene activation during embryonic development and cellular differentiation. SP-binding GC-box domains are common cis-regulatory elements present in the promoters of several genes expressed in a developmentally specific manner in differentiating mouse germ cells. Four Sp1 cDNAs were isolated from a mouse pachytene spermatocyte cDNA library and characterized by DNA sequence analysis.