Consequences of loss of PINCH2 expression in mice

Abstract

PINCH2 belongs, together with PINCH1, to a new family of focal adhesion proteins, the members of which are composed of five LIM domains. PINCH1 and PINCH2 interact, through their first LIM domain, with the integrin-linked kinase and thereby link integrins with several signal transduction pathways. Despite their high similarity, it has been shown that PINCH1 and PINCH2 could exert distinct functions during cell spreading and cell survival. To investigate the function of PINCH2 in vivo, we deleted PINCH2 in mouse using the loxP/Cre system. In contrast to the PINCH1-deficient mice, which die at the peri-implantation stage, PINCH2-null mice are viable, fertile and show no overt phenotype. Histological analysis of tissues that express high levels of PINCH2 such as bladder and kidney revealed no apparent abnormalities, but showed a significant upregulation of PINCH1, suggesting that the two PINCH proteins may have, at least in part, overlapping function in vivo. To further test this possibility, we established PINCH1-null mouse embryonic fibroblasts, which express neither PINCH1 nor PINCH2. We found that in fibroblasts with a PINCH1/2-null background, PINCH2 is able to rescue the spreading and adhesion defects of mutant fibroblasts to the same extent as PINCH1. Furthermore, we show that the LIM1 domain only of either PINCH1 or PINCH2 can prevent ILK degradation despite their failure to localize to focal adhesions. Altogether these results suggest that PINCH1 and PINCH2 share overlapping functions and operate dependently and independently of their subcellular localization.

Molecular dissection of the ILK-PINCH-parvin triad reveals a fundamental role for the ILK kinase domain in the late stages of focal-adhesion maturation

“…2A). In agreement with previous reports, ILK or PINCH1 deletion was accompanied by a trans-downregulation of PINCH1 and ILK, respectively (Fukuda et al, 2003;Li et al, 2005;Stanchi et al, 2005).…”

“…It has been shown in previous investigations that ILK -/-and PINCH1 -/-fibroblasts exhibit fewer and smaller FA than parental ILK fl/fl and PINCH1 fl/fl cells (Sakai et al, 2003;Stanchi et al, 2005). To explore the molecular basis of this phenotype, we analyzed the composition of ILK-and PINCH1-null adhesions by immunostaining.…”

“…Gene ablation is a powerful strategy for dissecting signaling cascades and establishing the functional hierarchy among different proteins within a pathway, but in the case of the IPP complex this analysis is complicated by the interdependency of the component proteins for their stability and localization in integrin plaques (Fukuda et al, 2003;Li et al, 2005;Stanchi et al, 2005;Zhang et al, 2002). Accordingly, western blot analysis showed that deletion of ILK or PINCH1 leads not only to the respective downregulation of PINCH1 or ILK proteins but also of α-parvin (Fig.…”

Focal adhesion complex proteins in epidermis and squamous cell carcinoma

“…100,101 The PINCH2-knockout mouse, however, is viable and fertile, with no apparent phenotype. 102 Both expressed at high levels in mouse skin, but their functional roles are unknown. 103 Several additional secreted glycoproteins have been reported to bind to and activate integrin αv heterodimers.…”

GPR17 gene disruption does not alter food intake or glucose homeostasis in mice

“…LIMS2 belongs to the family of focal adhesion proteins and functions as a component of the integrin signaling pathway (17). The small but significant reduction in Lims2 mRNA expression is unlikely to affect the metabolism of Gpr17 −/− mice because Lims2-deficient mice do not have an apparent phenotype (18) and Agrp expression was similar in Gpr17 −/− and wild-type mice.…”