A higher order of regulation can be achieved by compartmentalization and functional specialization of the endocytic pathway during signal transduction in response to growth factors (GFs). In contrast, impairment of intracellular (IC) trafficking of GF signaling complexes can result in mis-localization or accumulation of signaling molecules in the wrong compartment, or at the wrong time, giving rise to various disease states, including cancer. In addition, the specificity of motor protein light chains (LCs) in recruiting their membranous cargo for IC transport during regulation of GF signaling is becoming increasingly clear. Additional investigation of the regulation, key components, timing, and functional outcome of signaling from endosomal subcompartments is required to enable oncology drug development, based upon these newer signaling regimes. Our data from the last project period indicated that km23 dynein LCs are activated by TGF? receptors (T?Rs) and are required for Smad trafficking, prior to nuclear translocation. Thus, km23 appears to function as a """"""""motor receptor"""""""" to recruit TGF? signaling complexes to the dynein motor for IC transport of cargo (ie, T?Rs, Smads) along microtubules (MTs) toward the nucleus. In addition, we have identified another related member of the km23/LC7/robl/DYNLRB family, termed km23-2. While this isoform appears to have some characteristics similar to km23-1, km23-2 appears to more specifically regulate Smad3, in contrast to Smad2 regulation by km23-1. The mechanisms underlying the differential regulation and trafficking of Smads2/3 in relation to the km23-1/2 motor LCs will be explored in the new application, including how km23 impacts downstream TGF? responses. During the last project period, we have also shown that protein kinase A (PKA) directly phosphorylates km23 and is required for km23 binding to the dynein intermediate chain (DIC). The mechanisms underlying this PKA phosphorylation of km23 in TGF? signaling and Smad2/3 trafficking will also be examined. Additional studies relate to the investigation of how these trafficking events are altered in human ovarian cancer cells (HOCCs) known to express altered forms of km23-1. As part of the last project period, we identified km23-1 alterations in 42% of ovarian cancer patient tissues, with no km23 alterations detectable in normal tissues. Such a high alteration rate in ovarian cancer suggests that km23 may play an important role in either TGF2 resistance or tumor progression of this disease. In the new application, we will examine the effects of knocking down km23, or mutating it at key phosphorylation sites, on Smad trafficking, Smad-specific TGF? responses, and the malignant phenotype of the human cancer cells in vitro, as well as on tumor progression in vivo.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
Project #
Application #
Study Section
Tumor Cell Biology Study Section (TCB)
Program Officer
Salnikow, Konstantin
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Pennsylvania State University
Schools of Medicine
United States
Zip Code
Jin, Qunyan; Zhong, Yan; Mulder, Kathleen M (2013) Requirement for protein kinase A in the phosphorylation of the TGF? receptor-interacting protein km23-1 as a component of TGF? downstream effects. Exp Cell Res 319:897-907
Jin, Qunyan; Gao, Guofeng; Mulder, Kathleen M (2013) A dynein motor attachment complex regulates TGFß/Smad3 signaling. Int J Biol Sci 9:531-40
Jin, Qunyan; Liu, Guangming; Domeier, Phillip P et al. (2013) Decreased tumor progression and invasion by a novel anti-cell motility target for human colorectal carcinoma cells. PLoS One 8:e66439
Pandey, Manoj K; Liu, Guangming; Cooper, Timothy K et al. (2012) Knockdown of c-Fos suppresses the growth of human colon carcinoma cells in athymic mice. Int J Cancer 130:213-22
Jin, Qunyan; Ding, Wei; Mulder, Kathleen M (2012) The TGF? receptor-interacting protein km23-1/DYNLRB1 plays an adaptor role in TGF?1 autoinduction via its association with Ras. J Biol Chem 287:26453-63
Jin, Qunyan; Gao, Guofeng; Mulder, Kathleen M (2012) Requirement of a dynein light chain in transforming growth factor ? signaling in zebrafish ovarian follicle cells. Mol Cell Endocrinol 348:233-40
Jin, Qunyan; Pulipati, Nageswara R; Zhou, Weidong et al. (2012) Role of km23-1 in RhoA/actin-based cell migration. Biochem Biophys Res Commun 428:333-8
Pulipati, Nageswara R; Jin, Qunyan; Liu, Xin et al. (2011) Overexpression of the dynein light chain km23-1 in human ovarian carcinoma cells inhibits tumor formation in vivo and causes mitotic delay at prometaphase/metaphase. Int J Cancer 129:553-64
Jin, Qunyan; Gao, Guofeng; Mulder, Kathleen M (2009) Requirement of a dynein light chain in TGFbeta/Smad3 signaling. J Cell Physiol 221:707-15
Jin, Qunyan; Ding, Wei; Mulder, Kathleen M (2007) Requirement for the dynein light chain km23-1 in a Smad2-dependent transforming growth factor-beta signaling pathway. J Biol Chem 282:19122-32

Showing the most recent 10 out of 16 publications