Research Interests

        Cells connect and communicate via information
        superhighway named gap junctions. Gap junctions are
        clusters of transmembrane channels that connect the
        cytoplasms of adjacent cells. These channels permit
        small metabolites, ions and second messengers to pass
        from cell to cell. For cells like lens fibers within
        the interior of the vertebrate eye lens have neither a
        blood supply nor organelles, thus, lens survival and
        homeostasis are uniquely dependent on intercellular
        communication via gap junctions with the cells
        localized at the lens surface. For cells like bone
        osteocytes, signals generated by mechanical loading
        can be transmitted extensively at high speed through
        gap junction channels. Therefore, gap junctions
        provide critical means for cell survival and for
        physiological regulations of cellular functions. A
        wide variety of techniques are used in my laboratory
        including cell and tissue culture; fluorescence
        microscopy and cryosectioning; retroviral methodology;
        microinjection; molecular cloning techniques; protein
        isolation and analysis. Five projects are currently
        ongoing in my laboratory.

        Lens gap junctions.
        Previous studies show that mice deficient in one of
        the lens gap junction proteins, connexins, develop
        cataracts and microphthalmia, indicating the direct
        role of gap junction mediated cell communications in
        maintaining lens transparency and development. Lens
        fiber proteins, which survive the whole life span of
        animals, are susceptible to post-translational
        phosphorylation and evidence from other species has
        shown that phosphorylation of connexins is related to
        gap junction channel assembly and gating. The current
        research interests are: 1). To determine the
        functional role of connexin phosphorylation in the
        lens and its functional significance. 2). To
        characterize the relationships between lens connexins
        and major intrinsic protein (MIP) and the roles of MIP
        in formation of lens gap junctions. 3). To determine
        the roles of lens fiber connexins play in cell
        differentiation and lens development. 4). To
        characterize other lens proteins interacting with lens
        connexins.

        Osteocyte gap junctions
        Osteocytes are cells embedded in the matrix of bone
        and thought to be mechanosensory cells involved in the
        regulation of bone formation and remodeling. Gap
        junctions provide major pathways that transmit and
        coordinate the signals generated by mechanical stress.
        The current research interests are: 1). To identify
        the connexin(s) responsible for formation of
        functional gap junction channels in osteocytes. 2). To 
        determine the relationship(s) between mechanical
        loading and behavior of osteocyte gap junction
        channels. 3). Determine if gap junctions mediate the
        stimulatory effects on osteocyte regulatory factors
        induced by mechanical stress.

        Amino acid transporters
        Cellular metabolic needs are fulfilled by import of
        amino acids across the plasma membrane via specialized
        transporter proteins. Although many of the classical
        amino acid transporters have been characterized
        functionally, less than half of these transport
        proteins have been cloned. We have identified a new
        family of amino acid transporters. The current
        research interests are: 1). To characterize the
        functions of identified amino acid transporters. 2). To 
        understand the structure-function relationship of
        these transporters. 3). To explore the biological
        roles of the amino acid transporters play in vivo.